LIBRARY 

UNIVERSITY  OF 
CALIFORNIA 
SANTA  CRUZ 


MEMOIR 


JOHN   WILLIAM  DRAPER. 


1811-1882. 


GEORGE   F.   BAKKKR. 


KKAD  HKFOIIK  THK  NATIONAL  ACADK.MY,  APRIL  21,  1880. 


340 


LIBRARY  OF  THE 

USITEESITT  of  CALHOJIIII. 

LICK  OB8ERVAT®RY« 


BIOGRAPHICAL  MEMOIR  OF  JOHN  WILLIAM  DRAPER. 


MR.  PRESIDENT  AND  (JENTLEMEN  OF  THE  ACADEMY: 

Tlie  growth  of  science  (luring  the  last  half  century  is  nowhere 
better  illustrated  than  in  the  changes  which  have  taken  place  in 
our  views  with  regard  to  the  doctrine  of  energy.  Fifty  years  ago 
the  imponderables  held  full  sway  and  heat  light  and  electricity 
were  considered  forms  of  matter  quite  as  much  as  oxygen  and  sul- 
phur and  iron.  True  here  and  there  an  advanced  thinker  offered 
his  protests  against  this  conception  and  even  made  experiments  to 
prove  its  fallacy  ;  but  it  was  not  until  1844  that  Melloni  established 
the  essential  identity  of  radiant  light  and  heat,  and  not  until  1850 
that  Foucault  made  his  experimentum  crucis  with  regard  to  light. 
No  one  in  America,  it  is  believed,  had  a  larger  share  in  contrib- 
uting to  this  entire  revolution  of  scientific  opinion  than  the  eminent 
man  who  is  the  subject  of  this  notice.  For  more  than  forty  years 
he  labored  earnestly,  persistently,  successfully  in  the  field  of  radi- 
ant energy.  Viewed  from  the  standpoint  of  to-day  much  of  his 
work  may  be  criticised,  of  course ;  but,  as  he  himself  has  said,  to 
an  observer  "  imbued  with  the  true  spirit  of  philosophy  even  the 
shortcomings  which  are  detectable  in  it  are  not  without  a  charm. 
From  the  better  horizon  he  has  gained  he  watches  his  author,  who, 
like  a  pioneer,  is  doubtfully  finding  his  way,  here  traveling  on  a 
track  that  leads  to  nothing,  then  retracing  his  footsteps,  and  again, 
undeterred,  making  attempts  until  success  crowns  his  exertions. 
To  explore  the  path  to  truth  implies  many  wanderings,  many  in- 
quiries, many  mistakes." 

Jonx  WILLIAM  DRAPER  was  born  in  the  parish  of  St.  Helens, 
near  Liverpool,  England,  on  the  5th  of  May,  1811.  His  father, 
the  Uev.  John  C.  Draper,  was  a  clergyman  of  the  Wesleya.ii  de- 
nomination and,  like  others  in  the  same  calling,  was  in  quite 
moderate  circumstances.  He  was  always  greatly  interested  in 
scientific  subjects,  however,  especially  in  chemistry  and  astronomy, 
and  owned  a  (Jrogorian  reflecting  telescope,  with  which  he  made 

351 


NATIONAL    ACADEMY    OF    SCIENCES. 

many  observations.  Young  Draper  received  his  earlier  education 
in  his  own  home  from  private  tutors  employed  for  the  purpose ;  but 
at  the  age  of  eleven  he  was  sent  to  a  public  school  at  Woodhouse 
Grove,  then  supported  by  the  Wesleyans.  The  head  master  of  this 
school  was  an  American.  He  was  a  man  of  considerable  literary 
ability  and  had  contributed  several  articles  of  note  to  Rees'  Ency- 
clopedia, an  authority  then  in  great  repute.  Here  young  Draper 
devoted  himself  assiduously  to  his  classical  and  mathematical 
studies  and  with  marked  success.  So  that,  in  recognition  of  the  pro- 
gress he  had  made  in  scholarship,  he  was  selected  in  1824  to  deliver 
the  customary  address  from  the  school  to  the  Wesleyan  conference, 
which  met  that  year  at  Leeds.  This  was  his  first  public  oration 
and  it  made  a  great  impression  upon  him.  Not  long  after  this 
event,  however,  he  left  the  Woodhouse  Grove  school  and  returned 
home,  continuing  his  studies  there,  as  before,  under  private  tutors. 

In  the  year  1829  the  University  of  London  was  opened  for  in- 
struction. The  professor  of  chemistry  in  the  new  institution  was 
Dr.  Edward  Turner,  a  man  whose  reputation  as  a  chemist  placed 
him  among  the  first  in  England.  Young  Draper,  who,  with  his 
other  studies,  had  taken  up  the  study  of  science  and  had  already 
developed  a  decided  taste  for  investigation,  was  sent  to  Dr.  Turner's 
laboratory  to  receive  a  course  of  instruction  in  chemistry.  During 
the  two  or  three  years  which  were  thus  occupied  a  pleasant  and 
profitable  acquaintance  was  engendered,  which  ripened  into  a  life- 
long friendship.  Owing  to  the  unexpected  death  of  his  father,  how- 
ever, he  did  not  take  a  degree  at  the  University. 

Before  the  Revolutionary  War  certain  of  Draper's  ancestors  on 
his  mother's  side  had  come  to  America  and  had  settled  in  Virginia, 
founding  a  small  Wesleyan  colony.  Subsequently  others  of  the 
family  had  crossed  the  ocean  and  joined  the  colony.  Urged  by 
these  relatives  and  accompanied  by  his  mother  and  sister  Draper 
came  to  America  in  1832,  in  his  twenty-second  year.  The  expecta- 
tion of  receiving  a  professorship  in  the  denominational  college  in 
the  vicinity  was  one  of  the  strongest  inducements  held  out  to  him. 
Repeated  delays  in  starting,  however,  made  the  time  of  his  arrival 
much  later  than  had  been  anticipated  ;  so  that,  when  he  reached 
Virginia,  the  position  he  had  hoped  for  had  been  given  to  another 
person.  He  settled  with  his  relatives  at  Christiansville,  Mecklen- 
burg county,  where  he  devoted  himself  entirely  to  scientific  research. 

Although  before  leaving  England  he  had  published,  jointly  with 

352 


.JOHN    WILLIAM     DKAl'KU. 

a  Fellow  of  the  Geological  Society,  three  papers  on  scientific  sub- 
jects, yet  his  first  independent  contribution  to  science  was  from  this 
Christian  sville  laboratory.  It  appeared  in  the  American  Journal 
of  Science  and  Arts  for  July,  1834,  in  the  form  of  a  letter  to  the 
editors,  the  memoir  in  extenso  appearing  in  the  September  number 
of  the  Franklin  Institute  Journal  for  the  same  year  under  the  title 
"  Some  experimental  researches  undertaken  to  determine  the  nature 
of  capillary  action."  During  this  period  he  devoted  his  attention 
also  to  improvements  in  the  construction  of  galvanic  batteries,  to 
investigations  on  the  alleged  magnetic  action  of  light,  and  to  the 
analysis  of  a  native  chloride  of  carbon  and  of  certain  ancient  coins 
and  medals. 

Having  decided  to  take  the  degree  of  Doctor  of  Medicine  in  course 
Draper  spent  the  winters  of  1835  and  1836  in  Philadelphia  attend- 
ing the  medical  lectures  given  in  the  University  of  Pennsylvania. 
Here  he  came  directly  under  the  congenial  and  stimulating  influence 
of  Dr.  Robert  I  Tare's  instruction  in  chemistry  and  physics,  and  in  him 
and  in  Dr.  J.  K.  Mitchell,  at  that  time  the  professor  of  chemistry 
in  the  Jefferson  Medical  College,  he  found  warm  personal  friends. 
In  their  laboratories  he  did  a  large  amount  of  scientific  work,  and 
this  not  only  alone,  but  also  conjointly  with  these  eminent  men. 
lie  assisted  Dr.  Mitchell  when  he  used  for  the  first  time  in  this 
country  the  apparatus  of  Thilorier  for  the  liquefaction  of  carbonic- 
acid  gas. 

Draper  graduated  from  the  University  in  March,  1836.  The  sub- 
ject of  his  thesis,  as  given  in  the  Alumni  Catalogue,  was  "  Glandular 
Action.''  It  discussed  the  passage  of  gases  through  various  barriers 
not  having  visible  pores,  such  as  soap  bubbles.  He  showed  that 
these  transfusions  take  place  as  instantaneously  as  if  there  was  no 
obstacle  in  the  way  and  are  attended  by  many  curious  phenomena. 
He  put  one  gas  inside  the  bubble  and  another  on  the  outside ;  he 
then  analyzed  both  and  showed  that  the  movement  continues  until 
the  gaseous  constitution  is  the  same  within  and  without  the  bubble. 
The  special  application  of  these  experiments  was  to  ascertain  what 
goes  on  in  the  air  cells  of  the  lungs ;  how  oxygen  is  introduced  into 
the  blood  and  carbonic  acid  escapes  from  it  in  the  act  of  inspi ra- 
tion. Current  report  has  it  that  the  scientific  character  of  this 
thesis  secured  for  it  the  special  commendation  of  the  medical  faculty 
and  the  high  honor  of  publication  at  their  hands.  But  as  the  thesis 
itself  is  missing  from  the  collection  of  the  class  of  1836,  preserved 


NATIONAL    ACADEMY    OF    SCIENCES. 

in  the  college  records,  and  as  no  such  title  as  the  above  appears  in 
any  of  his  published  papers,  it  has  been  found  impossible,  to  verify 
the  statement.  Two  papers,  however,  covering  much  the  same 
ground  appeared  shortly  afterward.  The  first,  "  Experiments  on 
Endosmosis,"  came  out  in  the  Journal  of  the  Franklin  Institute  for 
March  and  July.  The  second,  entitled  "  Experiments  on  Absorp- 
tion," which  was  much  more  extended,  was  printed  in  the  Amer- 
ican Journal  of  the  Medical  Sciences  for  May. 

The  published  scientific  memoirs  of  Dr.  Draper  had  now  won 
for  him  a  very  considerable  reputation.  His  graduating  thesis 
had  by  its  originality  and  by  the  experimental  ability  shown  in  it 
attracted  the  attention  of  the  authorities  of  Hampden  Sidney  Col- 
lege, Prince  Edward  county,  Virginia.  Accordingly,  in  the  fall 
of  1836,  he  was  tendered,  and  accepted,  the  professorship  of  chem- 
istry and  natural  philosophy  in  that  institution.  This  appoint- 
ment was  especially  agreeable  to  him,  since  it  enabled  him,  as  he 
said,  "to  convert  experimental  investigation,  thus  far  only  an- 
amusement,  into  the  appropriate  occupation  of  his  life."  In  the 
new  sphere  of  labor  thus  opened  to  him  he  continued  his  scientific 
researches  with  largely  increased  experimental  facilities. 

In  1837  a  movement  was  made  to  establish  a  medical  school  in 
connection  with  the  University  of  the  city  of  New  York,  and  Dr. 
Draper  was  elected  professor  of  chemistry  in  the  new  institution. 
The  financial  embarrassments  of  that  year,  however,  crippled  the 
university  and  the  project  was  temporarily  abandoned. 

In  1839,  however,  he  was  elected  professor  of  chemistry  in  the 
undergraduate  department  of  that  university,  and  removed  with  his 
family  to  the  city  of  New  York.  In  1840,  in  conjunction  with  Drs. 
Mott,  Bedford,  Pattison,  and  Revere,  he  took  an  active  part  in 
organizing  the  medical  department,  in  which  he  became  the  pro- 
fessor of  chemistry.  His  intimate  relations  with  the  chancellor,  the 
Hon.  Theodore  Frelinghuyseu,  resulted  in  his  assuming  a  large 
share  in  the  preparation  of  the  constitution  of  the  new  department, 
to  the  wise  provisions  in  which  its  subsequent  prosperity  has  been 
largely  due.  Moreover,  in  doing  this  he  exerted  a  marked  influ- 
ence on  the  development  of  medical  science  in  the  city  of  New 
Yo'rk.  At  that  time  there  were  but  few  medical  students  there, 
probably  not  more  than  forty  or  fifty.  But  in  the  session  of  1841- 
'4*2  the  University  Medical  School  alone  enrolled  239  students,  and 
the  number  in  attendance  at  the  College  of  Physicians  and  Sur- 

354 


JOHN    WILLIAM    DRAPER. 

geons  was  also  largely  increased.  The  new  movement  was,  from 
the  first,  greatly  indebted  to  the  influence  exerted  in  its  favor  by  the 
New  York  Herald;  and  this  arose  out  of  the  relations  of  personal 
friendship  which  existed  between  Dr.  Draper  and  Mr.  James  Gor- 
don Bennett.  To  these  gentlemen,  it  has  been  said,  more  than  to 
any  others,  New  York  owes  its  present  advanced  position  as  regards 
medical  education.  Entire  pages  of  the  Herald  were  devoted  to 
reports  of  the  lectures  and  clinics  at  the  University;  and  a  strictly 
medical  journal,  published  by  Mr.  Bennett  and  called  The  Lancet, 
kept  the  doings  of  the  University  school  constantly  before  the  med- 
ical profession. 

The  first  president  of  the  new  medical  college  was  Dr.  Valentine 
Mott,  who  was  also  professor  of  surgery.  Dr.  Draper  was  elected 
secretary.  In  1850,  upon  the  resignation  of  Dr.  Mott,  he  succeeded 
to  the  presidency,  and  by  his  active  measures  and  wise  counsels, 
inaugurated  a  period  of  unexampled  prosperity  for  it.  In  his  own 
instruction  Dr.  Draper  had  always  maintained  that  the  functions 
of  an  organized  being  were  performed  under  the  operation  of  chem- 
ical and  physical  law,  in  opposition  to  the  theory  of  vital  force  then 
in  vogue  among  physiologists.  And  now,  when  the  new  views  of 
Liebig  and  his  school  gave  increased  importance  to  the  chemical 
relations  of  physiology,  he  was  among  the  first  to  recognize  their 
value,  and,  as  a  consequence  and  at  his  request,  physiology  was 
added  to  his  chair.  He  resumed  his  researches  on  physiological 
subjects,  and  his  lectures  were  replete  with  novel  and  radical  ideas. 

One  of  the  severest  trials  through  which  the  medical  department 
was  called  to  pass  during  Dr.  Draper's  presidency  was  the  entire 
destruction  by  fire,  in  1865,  of  its  college  building  in  Fourteenth 
street.  But  the  same  untiring  energy  which  had  secured  the  edi- 
fice that  was  destroyed  not  only  made  prompt  provision  for  the  con- 
tinuance of  the  lectures,  but  speedily  repaired  the  loss.  Though  in 
the  midst  of  the  course  of  instruction,  not  a  single  lecture  was  lost; 
and  in  the  fall  of  1869  he  gave  the  introductory  lecture  of  the  course 
in  the  new  building,  which  is  still  occupied  by  the  school,  and  which 
had  been  provided,  as  he  told  the  class,  by  the  generosity  of  Mr. 
Courtlandt  Palmer. 

Dr.  Draper's  personal  loss  was  especially  severe.  Not  only  were 
his  extensive  library,  his  lecture  notes,  and  the  note-books  which 
contained  the  results  of  his  experimental  investigations  consumed, 
but  his  entire  collection  of  chemical,  physical,  and  physiological 

355 


NATIONAL    ACADEMY    OF    SCIENCES. 

apparatus,  that  used  to  illustrate  his  lectures  as  well  as  that  more 
valuable  portion  which  he  had  used  in  his  researches,  was  destroyed. 
The  pecuniary  loss  he  estimated  at  $15,000.  This  was  the  second 
time  he  had  suffered  severely  by  fire.  In  1853  almost  the  entire 
edition  of  his  scientific  memoirs  and  essays  up  to  1844,  together 
with  the  illustrative  plates,  were  destroyed  by  fire  in  the  publishing 
house  of  Harper  &  Brothers. 

In  1873  Dr.  Draper  severed  his  connection  with  the  medical  de- 
partment of  the  University,  but  continued  his  instruction  in  chem- 
istry to  the  undergraduate  classes  until  1881,  the  year  preceding  his 
death. 

It  has  been  already  stated  that  Dr.  Draper  developed  very  early 
in  life  a  decided  fondness  for  science  and  scientific  investigation. 
It  is  said  that  his  decision  to  devote  himself  to  the  experimental 
study  of  nature  arose  from  the  accidental  observation  that  in  a  glass 
vessel  containing  camphor  beautiful  crystals  had  condensed  only  on 
the  illuminated  side.  A  desire  to  understand  the  cause  of  this  phe- 
nomenon led  him  to  read  whatever  books  he  could  obtain  which 
treated  of  the  chemical  and  mechanical  action  of  light,  of  adhesion 
and  of  capillary  attraction,  and  subsequently  to  experiment  for 
himself  in  these  and  similar  subjects. 

Capillary  attraction  was  the  subject  of  his  first  extended  research. 
Clairaut  had  already  shown  that  the  phenomenon  was  due  to  the 
adhesion  of  the  solid  for  the  liquid  as  compared  with  the  cohesion 
of  the  latter,  and  that  if  the  mutual  attraction  of  a  solid  and  a 
liquid  amount  to  half  the  cohesion  of  the  liquid  there  will  be  capil- 
lary depression ;  but  that  if  this  attraction  be  greater  than  half  the 
cohesive  value  the  liquid  will  rise  in  the  tube.  Dr.  Young  had 
maintained  that  the  bounding  meniscus  of  a  liquid  was  an  elastic 
surface  and  acted  by  its  tension  to  elevate  or  depress  the  column 
which  it  terminated.  And  Laplace,  in  the  more  elaborate  memoir 
contained  in  his  Theorie  de  1'action  Capillaire,  published  in  the 
supplement  to  the  tenth  book  of  his  Mecanique  Celeste,  had  at- 
tributed the  rise  or  fall  of  liquids  to  the  attraction  of  a  thin  layer  of 
the  liquid  immediately  adjacent  to  the  walls  of  the  tube.  Dr. 
Draper's  attention  was  first  drawn  to  the  subject,  as  he  tells  us,  dur- 
ing those  tiresome  moments  of  returning  health  which  follow  an 
autumnal  fever.  "  Perhaps,"  he  says,  "  if  there  be  any  merit  in  these 
experiments  it  may  hereafter  be  of  service  to  some  one  to  know  that 
they  were  begun  in  sickness  and  in  a  land  of  strangers ;  that  they 

356 


JOHN    WILLIAM    DRAPER. 

were  pursued  in  all  the  calamity  of  family  bereavement,  and  in  the 
depths  of  forests,  alike  unused  to  music,  to  poetry,  to  philosophy." 
His  first  experiments  were  addressed  to  the  direct  determination  of 
the  attraction  between  mercury  and  glass,  with  the  view  of  testing 
Clairaut's  mathematical  deduction.  After  repeated  trials  he  found 
that  a  strong  and  uniform  adhesion  was  obtained  when  the  mercury 
was  pure  and  warm  and  the  glass  perfectly  clean.  Repeating  the 
experiment  with  an  amalgamated  disk  of  copper,  of  the  same  size, 
the  weight  required  for  separation  was  regarded  as  measuring  the 
cohesion  of  the  mercury  itself.  The  results  of  a  number  of  experi- 
ments showed  that  in  no  case  did  the  attraction  of  mercury  for 
glass  amount  to  half  the  cohesion  of  the  mercury.  But  since  a  glass 
plate  on  the  surface  of  water  is  wetted,  even  after  separation,  it  is 
obvious  that  in  this  case  the  adhesion  is  greater  than  the  whole  co- 
hesion ;  hence  the  rise  of  water  in  a  tube  of  glass  is  easily  accounted 
for. 

But  an  unexpected  phenomenon  was  developed.  On  connecting 
the  mercury,  dry  and  warm,  to  a  gold  leaf  electroscope  no  disturb- 
ance of  the  leaves  took  place  so  long  as  the  glass  plate  was  in  con- 
tact with  its  surface.  But  on  separating  them — and  it  required 
considerable  force  to  do  this — both  the  mercury  arnd  the  glass  be- 
came strongly  electrified,  the  mercury  being  negative  and  the  glass 
positive.  Indeed,  the  development  of  electrification  was  so  de- 
cided as  to  tear  asunder  the  leaves  of  the  electroscope.  Dr.  Draper 
naturally  concluded  that  contact  of  mercury  and  glass  developed 
electrification  ;  that  while  in  contact  the  electricity  was  "  disguised  " 
and  appeared  only  on  separation  ;  and  that  since  the  two  were  op- 
positely and  strongly  electrified,  the  force  requi red  to  separate  them 
measured  the  electrical  attraction.  But  this  force  measured  also 
the  adhesion,  by  hypothesis;  and  hence  adhesion  must  be  an  electri- 
cal attraction.  Two  striking  confirmations  of  this  theory  are  given 
in  the  memoir.  In  the  first  he  repeated  the  mercury  experiment 
with  disks  of  glass,  gum-lac,  sealing  wax,  sulphur,  and  beeswax,  and 
proved  that  the  electrification,  as  measured  with  the  torsion  balance, 
was  for  each  disk  proportional  to  the  adhesion  as  measured  by  the 
force  required  for  separation  ;  and  that  for  the  several  disks  ex- 
amined the  values  obtained  diminished  in  the  above  order.  In  the 
second  he  showed  very  ingeniously  that  electrification  exercises  an 
apparent  control  over  all  the  phenomena  of  capillary  attraction. 
One  form  of  his  apparatus  consisted  of  an  inverted  siphon,  the 

357 


NATIONAL    ACADEMY    OF    SCIENCES. 

larger  leg  being  about  half  an  inch  and  the  smaller  about  one- 
tenth  of  an  inch  in  diameter.  Mercury  is  poured  into  the  larger 
and  dilute  sulphuric  acid  into  the  smaller  tube,  the  latter  liquid 
resting  on  .the  former.  On  connecting  the  mercury  with  the 
negative  terminal  of  a  voltaic  battery  and  the  acid  with  the  positive 
the  mercury  falls  in  the  tube.  Reverse  the  battery-terminals  and 
the  mercury  column  rises.  Moreover,  Dr.  Draper  observes  that  all 
these  changes  in  position  are  accompanied  by  certain  definite  changes 
of  figure  of  the  bounding  surface,  and  shows  that  this  might  have 
been  expected  from  the  theory  of  Laplace.  Placing  a  globule  of 
mercury  in  acidulated  water  in  contact  with  the  negative  terminal 
of  the  battery  he  found  that  whenever  contact  of  the  positive  termi- 
nal was  made  with  the  acid  an  instant  deformation  of  figure  took 
place,  the  upper  surface  being  flattened,  so  that  the  mercury  touched 
the  inclosing  tube  all  around  in  a  complete  ring.  This  memoir, 
published  in  1834,  must  be  considered  in  all  respects  a  remarkable 
one,  and  anticipates  clearly  many  of  the  more  important  later  dis- 
coveries. 

The  phenomenon  of  osmose  described  by  Dutrochet  in  1827  had 
been  noticed  by  Dr.  Draper  in  the  above  memoir.  A  few  years 
later  Dr.  J.  K.  Mitchell  had  published  a  valuable  paper  on  the 
osmotic  phenomena  observed  in  membranes  of  caoutchouc.  When 
Dr.  Draper  entered  upon  his  medical  studies  in  Philadelphia,  there- 
fore, it  was  natural  that  he  should  take  a  lively  interest  in  the  phe- 
nomena referred  to,  and  particularly  in  their  physiological  relations. 

His  experiments  on  gaseous  osmose  were  original  and  important 
and  were  based  on  the  simple  assumption  that  any  substance  in 
contact  with  any  other  tends  to  diffuse  into  it.  He  found  that  am- 
monia gas  penetrated  almost  instantly  films  of  shellac,  gold  leaf 
and  mica,  and  especially  liquid  films,  whether  these  were  thin,  as  in 
a  soap  bubble,  or  were  composed  of  a  layer  of  water  of  quite  con- 
siderable thickness.  When  such  a  layer  separated  carbonic-acid 
and  hydrogen  gases,  for  example,  he  observed  that  the  phenomenon 
was  a  simple  one  and  consisted  in  the  mutual  solution  of  the  gases 
in  the  liquid,  their  transference  through  the  film,  and  their  subse- 
quent evaporation,  the  process  ceasing  when  the  atmosphere  on  both 
sides  of  the  layer  was  the  same.  Using  then  a  membrane  of  caout- 
chouc he  sought  to  discover  whether  gaseous  osmose  could  be  pre- 
vented by  pressure  ;  and  he  experimentally  proved  that  sulphur- 
ous acid  passed  into  air  under  a  pressure  of  7£  atmospheres,  car- 

358 


JOHN    WILLIAM    DKA1MOK. 

bonic  acid  under  one  of  10  atmospheres,  and  hydrogen  sulphide 
under  a  pressure  of  24.1  atmospheres.  Since  the  force  impelling 
the  particles  of  one  gas  into  the  interstices  of  another,  without  a 
septum,  never  exceeds  the  pressure  of  one  atmosphere,  it  is  plain 
that  the  source  of  this  remarkable  power  must  lie  in  the  membrane 
itself.  So  that  the  caoutchouc  membrane  must,  in  this  experiment, 
have  condensed  the  sulphurous-acid  gas  and  the  hydrogen-sulphide 
gas  into  liquids,  which  were  then,  in  this  condition,  transferred 
through  the  film  and  evaporated  on  the  other  side  precisely  as  with 
the  water  film.  • 

AVith  regard  to  liquid  osmose  Dr.  Draper  shows  that  the  only 
essentials  are :  First,  that  both  the  liquids  should  wet  the  barrier ; 
second,  that  they  should  rise  to  different  heights  in  tubes  made  of  it, 
and,  third,  should  be  capable  of  uniting  chemically  with  each  other. 
All  solid  bodies  which  act  as  barriers  have  pores,  which,  while  too 
small  to  permit  leakage,  yet  allow  interchange  of  indefinitely  small 
columns  of  liquid.  Such  are  plates  of  Villarica  porcejain  clay,  of 
Bru/il  indurated  steatite,  and  of  certain  varieties  of  compact  sand- 
stone. No  liquid  can  pass  a  barrier  the  pores  of  which  it  cannot 
wet;  but,  since  water  by  electrifying  it  positively  may  be  made  to 
wet  mercury,  electricity  modifies  osmose.  The  separation  of  water 
from  litmus  through  a  membrane  having  alcohol  on  its  other  side, 
he  concludes,  is  "  only  a  refined  kind  of  filtration,  which,  probably, 
may  hereafter  become  of  considerable  importance  in  its  applications 
in  the  arts,  as  in  the  separation  of  coloring  matter  from  solutions, 
or  the  preparation  of  medicines,  such  as  the  vegetable  alkalies,  which 
should  be  formed  from  colorless  solutions." 

In  a  paper  published  in  1846  Dr.  Draper  applies  these  principles 
very  ingeniously  to  explain  the  circulation  of  the  sap  in  plants  and 
the  blood  in  animals.  Both  these  motions,  he  says,  depend  on  the 
following  simple  physical  principle:  "That  if  two  liquids  communi- 
cate with  one  another  in  a  capillary  tube  or  in  a  porous  or  paren- 
chymatous  structure  and  have  for  that  tube  or  structure  different 
chemical  affinities  movement  will  ensue  ;  that  liquid  which  has  the 
most  energetic  affinity  will  move  with  the  greatest  velocity  and  may 
even  drive  the  other  fluid  entirely  before  it."  In  the  rootlet  the 
phenomenon  is  simply  an  osmotic  one,  a  flow  taking  place  from  the 
water  without  into  the  mucilaginous  sap  within,  precisely  as  water 
flows  into  gum-water  through  a  bladder.  In  the  leaf  the  weak 
ascending  watery  sap  rises  to  its  upper  surface  and  there  obtains 

359 


NATIONAL    ACADEMY    OF    SCIENCES. 

carbonic  acid  from  the  air.  The  sunlight  effects  the  decomposition 
of  this,  changing  it  to  a  mucilaginous  solution.  On  the  principle 
now  indicated  the  water  will  drive  the  mucilaginous  solution  before 
it,  forcing  it  back  along  its  proper  vessels  into  the  stem.  The  flow 
of  the  sap  in  plants  therefore  is  controlled  by  sunlight,  since  this 
agent  determines  the  production  of  the  mucilaginous  solution,  which 
is  the  motive  power.  When  the  season  advances  the  flow  slackens, 
because  the  formation  of  the  elaborated  sap  diminishes.  Both  in 
the  rootlet  and  in  the  leaf  consequently  the  action  is  due  to  the 
fact  that  two  different  liquids  are  brought  in  contact  with  a  porous 
solid,  which  is  wetted  by  both  of  them,  but  unequally.  Hence  that 
one  which  has  the  greatest  affinity  for  the  solid  and  wets  it  most 
perfectly  passes  most  rapidly  through  it  and  drives  the  other  one 
before  it.  The  descent  of  the  elaborated  sap  is  therefore  quite  as 
positive  an  action  as  the  ascent  of  the  unelaborated. 

In  animals  the  blood  in  the  arterial  capillaries  of  the  systemic 
circulation  is  charged  with  oxygen,  which  has  an  intense  affinity  for 
the  carbon  and  hydrogen  of  the  walls.  In  the  venous  capillaries 
the  blood  is  charged  with  carbonic  acid  having  no  affinity  for  these 
tissues.  The  arterial  blood  will  drive  the  venous  blood  before  it, 
therefore.  In  the  pulmonic  system  the  venous  blood  is  presented  to 
the  air  cells,  for  the  oxygen  in  which  it  has  a  strong  affinity,  while, 
the  arterial  blood  which  has  absorbed  this  oxygen  has  no  longer 
any.  Movement  ensues  as  before,  but  as  now  the  affinities  arc 
reversed  the  flow  is  from  the  veins  to  the  arteries.  The  systemic 
circulation  is  due  therefore  to  the  oxidizing  action  of  the  arterial 
blood  and  the  flow  is  from  the  artery  to  the  vein.  The  pulmonary 
circulation  is  due  to  the  oxidation  of  the  venous  blood  and  the  flow 
is  from  the  venous  to  the  arterial  side.  Both  arise  from  the  common 
principle  that  "a  pressure  will  always  be  exerted  by  the  fluid  which 
is  ready  to  undergo  a  change  upon  that  which  has  already  under- 
gone it — a  pressure  which,  as  there  is  no  force  to  resist  it,  will 
always  give  rise  to  motion  in  a  direction  from  the  changing  to  the 
changed  liquid." 

"A  true  theory,"  says  Dr.  Draper,  "  is  like  a  window  of  crystal 
glass,  through  which  we  can  see  all  objects  in  their  proper  positions 
and  colors  and  relations,  no  matter  whether  they  are  such  as  are 
near  or  those  that  are  at  a  distance  ;  no  matter  whether  they  are 
directly  before  us  or  enter  only  obliquely  into  the  field  of  view. 
A  fictitious  theory  is  like  a  Venetian  blind,  which  has  to  be  set  in  a 

360 


JOHN    WILLIAM    DKAI'KR. 

certain  position  with  respect  to  the  observer  and  only  shows  him 
objects  for  which  it  lias  been  adjusted,  and  those  in  an  unsatisfactory 
manner;  but  if  he  moves  to  one  side  or  to  the  other,  or  endeavors  to 
see  objects  which  are  not  directly  in  his  way,  his  view  is  intercepted, 
or,  perhaps,  unless  he  makes  a  new  adjustment,  the  light  is  shut  out 
altogether." 

It  is,  however,  by  his  researches  upon  Radiant  Energy  that  John 
W.  Draper  is  best  known  in  the  world  of  science.  In  an  able 
memoir  on  the  Production  of  Light  by  Heat,  published  in  1847, 
he  described  some  ingenious  experiments  with  incandescent  platinum, 
by  which  he  conclusively  proved  :  First,  that  the  temperature  at 
which  this  metal  became  incandescent  was  fixed  and  constant  at 
977°  F. ;  and,  second,  that  various  other  substances,  such  as  brass, 
antimony,  gas  carbon,  lead,  and  the  like,  all  became  luminous  at  the 
same  temperature,  which  was  that  of  the  gun  barrel  in  which  they 
were  inclosed.  By  means  of  an  extemporized  spectroscope  he  ex- 
amined the  platinum  as  its  temperature  was  gradually  raised  by  the 
electric  current  and  showed  that  as  this  temperature  rose  from 
1,095°  to  2,130°  F.  the  spectrum  gradually  extended  itself  toward 
the  violet;  rays  of  an  increasing  refrangibility  being  successively 
produced,  the  frequency  of  the  vibrations  increasing  with  the  tem- 
perature. In  order  to  bring  these  observations  to  a  common  standard 
of  comparison  Dr.  Draper  originated  the  simple  device  of  using  the 
sun  spectrum  with  its  fixed  lines  as  a  reference-spectrum,  daylight 
being  reflected  to  the  prism  through  a  narrow  aperture  occupying 
exactly  the  position  in  which  the  platinum  strip  was  to  be  subse- 
quently placed.  The  relation  of  the  temperature  of  incandescent 
platinum  to  the  amount  of  light  emitted  by  it  was  also  examined, 
and  it  was  found,  photometrically,  that  at  2,590°  F.  the  light  emitted 
was  more  than  thirty-six  times  as  much  as  that  given  out  by  the  same 
strip  of  metal  at  1,900°.  Moreover,  on  measuring,  by  means  of  the 
thermo-pile,  the  total  energy  radiated  from  the  incandescent  strip, 
he  found  that  if  he  took  the  heat  radiated  at  980°  as  unity,  that 
emitted  at  2,360°  was  17.8;  the  heat  radiated  between  1,000°  and 
1,300°  being  nearly  the  same  in  amount  as  that  radiated  in  passing 
from  common  temperatures  up  to  1,000°.  In  closing  this  memoir 
the  author  says :  *'  The  preceding  experiments  furnish  an  easy  means 
of  supplying  *  *  *  what  might  be  termed  a  '  unit  lamp.'  A 
surface  of  platinum  of  standard  dimensions,  raised  to  a  standard 
temperature  by  a  voltaic  current,  will  always  emit  a  constant  light. 

361 


NATIONAL    ACADEMY    OF    SCIENCES. 

A  strip  of  that  metal  one  inch  long  and  one-twentieth  of  an  inch 
wide,  connected  with  a  lever  by  which  its  expansion  might  be  meas- 
ured, would  yield  at  2,000°  a  light  suitable  for  most  purposes.  More- 
over, it  would  be  very^easy  to  form  from  it  a  photometer  by  screen- 
ing portions  of  the  shining  surface.  An  ingenious  artist  would  have 
very  little  difficulty,  by  taking  advantage  of  the  movements  of  the 
lever,  in  making  a  self-acting  apparatus,  in  which  the  platinum 
should  be  maintained  at  a  uniform  temperature,  notwithstanding  any 
change  taking  place  in  the  voltaic  current." 

In  the  following  year  Dr.  Draper  published  a  noteworthy  memoir 
on  the  production  of  light  by  chemical  action.  In  this  memoir  he 
investigates  by  means  of  the  prism  the  character  of  the  light  which 
is  produced  by  combustion,  answering  thus  his  own  query,  "  Can 
any  connection  be  traced  between  the  chemical  nature  of  a  substance 
or  the  conditions  under  which  it  burns  and  the  nature  of  the  light 
which  it  emits  ?"  With  a  slit,  a  prism,  and  an  observing  telescope 
he  examined  the  flames  of  oil,  of  alcohol,  of  alcoholic  solutions 
of  boric  acid  and  strontium  nitrate,  of  phosphorus,  of  sulphur,  of 
carbonic  oxide,  of  hydrogen,  of  cyanogen,  and  of  arsenetted  hydro- 
gen. The  flame  of  the  oil  was  yellow ;  of  the  alcohol,  pale  blue ;  of 
the  boric  acid,  green;  of  the  strontium,  red;  of  the  phosphorus, 
yellowish  white;  of  the  sulphur  and  carbonic  oxide,  blue;  of  the 
hydrogen,  pale  yellow ;  of  the  cyanogen,  lilac,  and  of  the  arsenetted 
hydrogen,  white.  "Notwithstanding  this  diversity  of  color,"  he 
says,  "all  these  flames,  as  wTell  as  many  others  that  I  have  tried, 
yield  the  same  result;  every  prismatic  color  is  found  in  them.  Even 
in  those  cases  where  the  flame  is  very  faint,  as  in  alcohol  and  in  hy- 
drogen gas,  not  only  may  red,  yellow,  green,  blue,  and  violet  light 
be  traced,  but  even  bright  Fraunhoferian  lines  of  different  colors." 
The  spectra  given  by  these  variously-colored  flames  were  carefully 
drawn  and  their  peculiarities  were  pointed  out.  When,  he  thus 
examined  the  flame  of  cyanogen  he  beheld,  as  he  says,  "  a  spectrum 
so  beautiful  that  it  is  impossible  to  describe  it  by  words  or  depict  it 
in  colors.  It  was  crossed  throughout  its  extent  by  black  lines  sep- 
arating it  into  well-marked  divisions.  I  could  plainly  count  four 
red  rays  of  definite  refrangibility,  followed  by  one  orange,  one  yel- 
low, and  seven  green  rays,  while  in  the  more  refrangible  spaces  were 
two  extensive  groups  of  black  lines,  recalling  somewhat  from  their 
position,  but  greatly  exceeding  in  extent,  Fraunhofer's  lines  G  and 
H  in  the  sun's  rays."  He  considered  the  interior  lilac  cone  to  be 

362 


JOHN    WILLIAM    DRAPER. 

the  source  of  the  fixed  lines  of  the  bright  spectrum,  and  he  observed 
that  new  lines  are  developed  as  the  temperature  rises.  "  Do  not  the 
various  facts  here  brought  forward,"  he  says,  "prove  that  chemical 
combinations  are  attended  by  a  rapid  vibratory  motion  of  the  par- 
ticles of  the  combining  bodies,  which  vibrations  become  more  fre- 
quent as  the  chemical  action  is  more  intense  ?  "  This  memoir  may 
be  regarded  as  one  of  the  earliest  contributions  to  spectrum  analysis. 

In  a  subsequent  memoir,  written  in  1857,  Dr.  Draper  uses  the  fol- 
lowing remarkable  language :  "  In  other  cases  dark  lines  are  replaced 
by  bright  ones,  as  in  the  well-known  instance  of  the  electric  spark 
between  metallic  electrodes.  The  occurrence  of  lines,  whether  bright 
or  dark,  is  hence  connected  with  the  chemical  nature  of  the  substance 
producing  the  flame.  For  this  reason  these  lines  merit  a  much  more 
critical  examination,  for  by  their  aid  we  may  be  able  to  ascertain 
points  of  great  interest  in  other  departments  of  science.  Thus,  if 
we  are  ever  able  to  acquire  certain  knowledge  respecting  the  physi- 
cal state  of  the  sun  and  other  stars,  it  will  be  by  an  examination  of 
the  light  they  emit."  Surely  these  researches,  with  the  prophetic 
conclusions  which  he  drew  from  them,  entitle  Professor  Draper  to  a 
recognized  position  among  the  pioneers  in  the  science  of  prismatic 
analysis. 

Some  of  the  earliest  of  Dr.  Draper's  investigations  were  directed 
to  a  determination  of  the  various  forms  of  energy  which  exist  in 
solar  light.  The  chemical  action  of  light  was  always  a  fascinating 
subject  to  him  and  he  had  made  many  interesting  experiments  to 
ascertain  the  effect  of  different  kinds  of  light  upon  chemical  change. 
These  chemical  actions  were  investigated  in  three  different  direc- 
tions. The  first  of  these  was  photography.  For  many  years  he 
had  studied  the  action  of  light  in  changing  the  color  of  metallic 
salts,  and  he  had  already  long  been  accustomed  to  apply  the  photo- 
graphic process  to  the  solution  of  physical  problems  when  Daguerre's 
discovery  was  announced  in  1839.  He  welcomed  the  daguerreotype 
enthusiastically,  made  a  special  study  of  it,  and  in  the  same  year 
improved  it  so  much  that  he  took  by  its  means  the  first  portrait  of 
the  human  face.  In  these  days  of  rapid  emulsion  processes  the 
directions  he  gives  for  taking  a  daguerreotype  appear  interesting. 
"  In  the  first  experiments  I  made,"  he  says,  "  the  face  of  the  sitter 
was  dusted  with  a  white  powder,  but  a  few  trials  showed  that  this 
was  unnecessary."  "On  a  bright  day  and  with  a  sensitive  plate  por- 
traits can  be  obtained  in  the  course  of  five  or  seven  minutes  in  the 

363 


NATIONAL    ACADEMY    OF    SCIENCES. 

diffused  daylight  even  when  an  ammonia-sulphate  of  copper  cell 
is  interposed.  The  hands  should  never  rest  upon  the  chest,  for 
the  motion  of  respiration  disturbs  them  so  much  as  to  make  them 
of  a  thick  and  clumsy  appearance,  destroying  also  the  representa- 
tion of  the  veins  on  the  back,  which,  if  they  are  held  motionless, 
are  copied  with  surprising  beauty.  A  person  dressed  in  a  black 
coat  and  open  waistcoat  of  the  same  color  must  put  on  a  temporary 
front  of  a  drab  or  flesh  color,  or  by  the  time  that  his  face  and  the 
fine  shadows  of  his  woolen  clothing  are  evolved  his  shirt  will  be 
solarized  and  be  blue  or  even  black,  with  a  white  halo  around  it. 
Owing  to  the  circumstance  that  yellow  and  yellowish  browns  re- 
quire a  long  time  to  impress  the  substance  of  the  daguerreotype 
persons  whose  faces  are  freckled  all  over  give  rise  to  the  most  ludi- 
crous results — a  white  portrait  mottled  with  just  as  many  black 
dots  as  the  sitter  has  yellow  ones."  On  the  23d  of  March,  18-10, 
Dr.  Draper  presented  to  the  Lyceum  of  Natural  History  of  New 
York  the  first  representation  of  the  moon's  surface  ever  taken  by 
photography.  The  daguerreotype  plate  was  exposed  twenty  minutes 
and  the  image  was  about  an  inch  in  diameter.  In  this  image  the 
places  of  the  dark  spots  can  be  indistinctly  traced. 

The  second  method  by  which  he  studied  the  action  of  the  chemi- 
cal rays  was  based  upon  the  effect  which  they  produced  upon  chlorine 
gas.  In  1843  he  announced  to  the  British  Association  that  this  gas 
underwent  a  decided  modification  under  the  influence  of  sunlight,  in 
consequence  of  the  absorption  of  these  chemical  rays.  In  virtue  of 
this  change  in  its  character  it  was  now  able  to  unite  directly  with 
hydrogen,  a  property  not  possessed  by  chlorine  kept  in  the  dark. 
Hence  he  announced  the  discovery  of  a  new  imponderable  in  solar 
light  which  was  analogous  to  light  and  heat,  and  which  was  the 
agent  producing  chemical  change.  To  this  new  agent  he  gave  the 
name  "  tithonicity,"  the  origin  of  which  he  thus  describes  :  "  The 
chemical  rays  are  associated  with  the  rays  of  light,  accompanying 
them  in  all  their  movements,  originating  with  them,  and,  unless 
disturbed,  continuing  to  exist  along  with  them.  But  should  a  com- 
pound beam  like  this  fall  upon  a  sensitive  surface  the  chemical  rays 
sink  into  it,  as  it  were,  and  lose  all  their  force,  and  the  rays  of  light 
are  left  alone.  Photographic  results  thus  obtained  from  the  repos- 
ing of  the  chemical  rays  on  the  sensitive  surface  are  not,  however, 
in  themselves  durable,  for  the  rays  escape  away  under  some  new 
form.  Tithonus  was  a  beautiful  youth  whom  Aurora  fell  in  love 

364 


JOHN    WILLIAM    DRAPER. 

with  and  married  in  heaven.  The  fates  had  made  him  immortal ; 
but,  unlike  his  bride,  in  the  course  of  events  he  became  feeble  and 
decrepit,  and,  losing  all  his  strength,  was  rocked  to  sleep  in  a  cradle. 
The  goddess,  pitying  his  condition,  metamorphosed  him  into  a  grass- 
hopper. The  fact  and  the  fable  agree  pretty  well,  and,  indeed,  the 
playful  coincidence  might  be  carried  much  farther.  The  powers  of 
photography,  which  bring  architectural  remains  and  the  forms  of 
statuary  so  beautifully  and  impressively  before  us,  might  seem  to  be 
prefigured  by  the  speaking  image  of  the  son  of  Tithonus  and  Au- 
rora that  was  to  be  seen  in  the  deserts  of  Egypt.  Besides  this  such 
words  as  tithonoscope,  tithonometer,  tithonography,  tithonic  effect, 
ditithonescence  are  musical  in  an  English  ear."  In  the  same  year 
he  described  a  tithonometer  or  instrument  for  measuring  these  chem- 
ical rays  based  on  their  action  upon  chlorine.  The  apparatus  con- 
sisted of  an  inverted  siphon  tube,  the  shorter  limb  of  which  was 
closed,  the  longer  drawn  out  and  graduated.  By  means  of  wires  of 
platinum  sealed  into  the  shorter  limb  the  solution  of  hydrochloric 
acid  which  it  contained  could  be  decomposed  by  a  voltaic  current, 
and  this  limb  filled  with  mixed  hydrogen  and  chlorine  gases.  When 
the  image  of  a  flame,  formed  by  a  convex  lens,  was  caused  to  fall 
on  the  sentient  tube  the  liquid  in  the  longer  limb  began  instantly  to 
descend,  moving  regularly  over  the  scale  so  long  as  the  exposure  was 
continued.  This  instrument,  while  much  simpler,  appears  to  be 
quite  as  sensitive  as  the  one  described  by  Bunsen  and  Koscoe  many 
years  later  (1856). 

The  third  method  which  Dr.  Draper  employed  for  studying  the 
action  of  the  chemical  rays  was  based  on  the  growth  of  plants. 
Already,  in  1837,  he  had  investigated  the  phenomenon  of  the  de- 
composition of  solar  light  by  leaves,  and  had  shown  that  these  leaves 
absorbed  certain  rays.  But  these  early  experiments  were  made 
under  colored  glasses  and  were  not  entirely  conclusive,  other  rays 
passing  simultaneously  through  the  media  used.  When  seeds  were 
made  to  germinate  under  these  glasses,  however,  he  found  that  the 
plants  under  the  red  and  the  violet  glasses  were  as  perfectly  etiolated 
as  if  they  had  been  kept  in  the  dark ;  while  those  under  the  yellow 
glass  promptly  assumed  a  green  color  and  developed  rapidly.  In 
order  to  obviate  the  objection  raised  to  colored  glasses  a  crop  of 
seeds  was  caused  to  germinate  in  a  long  box  placed  in  the  dark  and 
the  young  plants  were  then  exposed  to  the  action  of  a  solar  spectrum. 
Those  in  the  yellow  speedily  turned  green,  while  those  in  the  red 
(2)  365 


NATIONAL    ACADEMY    OF    SCIENCES. 

and  in  the  violet  regions  remained  unaffected.  An  attempt  was 
then  successfully  made  to  effect  the  decomposition  of  carbonic-acid 
by  the  green  parts  of  plants  also  placed  in  the  solar  spectrum.  Water 
freed  from  air  by  boiling  was  saturated  with  carbonic  acid  gas,  and 
in  it  was  immersed  grass  whose  surfaces  had  been  carefully  freed  of 
air.  Seven  tubes  thus  prepared  were  placed  each  in  one  of  the  seven 
colors  of  the  spectrum  and  carefully  observed.  In  a  few  minutes 
after  the  beginning  of  the  experiment  the  tubes  on  which  the  orange, 
the  green,  and  the  yellow  rays  fell  began  to  give  off  minute  bubbles 
of  gas,  and  in  an  hour  and  a  half  sufficient  was  collected  for  accurate 
measurement.  Forty-three  volumes  of  gas  were  produced  in  the 
yellow-green,  twenty -four  and  three-fourth  volumes  in  the  red-orange, 
four  and  one-tenth  in  the  green-blue,  one  in  the  blue,  and  none  in 
the  other  colors.  The  memoir  in  which  these  results  were  first  pub- 
lished was  read  to  the  American  Philosophical  Society  on  the  occa- 
sion of  its  centennial  anniversary  in  1843. 

But  it  was  mainly  by  means  of  spectrum  investigations  that  Dr. 
Draper  studied  the  components  of  radiant  energy.  In  the  earlier 
stages  of  his  work  he,  in  common  with  his  contemporaries,  regarded 
heat  and  light  as  imponderable  agents,  entirely  distinct  from  one 
another,  though  coexisting  in  solar  light.  In  his  later  memoirs* 
however,  having  accepted  the  essential  unity  of  radiant  energy,  he 
discusses  with  great  ability,  in  his  memoir  of  1872,  on  the  distribu- 
tion of  the  chemical  force  in  the  spectrum,  the  dependence  of  the 
result  upon  the  nature  of  the  surface  upon  which  the  light  falls.  In 
this  memoir  he  shows :  First,  that  so  far  from  chemical  influences 
being  restricted  to  the  more  refrangible  rays  every  part  of  the  spec- 
trum, visible  and  invisible,  can  produce  chemical  changes  and  can 
modify  the  molecular  arrangement  of  bodies ;  and,  second,  that  the 
rays  effective  in  producing  chemical  or  molecular  changes  in  any 
special  substance  are  determined  solely  by  the  absorptive  power  of 
that  substance.  Thus  silver  salts,  for  example,  blacken  most 
readily  in  the  more  refrangible  regions.  But  even  these  have  their 
peculiarities.  An  iodide  of  silver  plate  long  exposed  to  the  spectrum  ? 
with  absolute  exclusion  of  extraneous  light,  is  normally  darkened 
in  the  more  refrangible  and  receives  a  white  stain  in  the  less  re- 
frangible regions.  If,  however,  the  plate  receive  weak  diffused 
light  during  exposure  it  will  be  found  on  developing  that  every  ray 
that  the  prism  can  transmit,  from  below  the  extreme  red  to  beyond 
the]extreme  violet,  has  been  active.  Indeed,  it  was  by  this  very  process 

360 


JOHN    WILLIAM    DRAPER. 

that  Dr.  Draper,  in  1843,  discovered  the  dark  lines  «,  ft,  ?  in  the 
ultra-red.  Essentially  the  same  results  are  obtained  if  the  plate  is 
submitted  to  a  weak  light  for  a  few  moments  previous  to  its  ex- 
posure to  the  spectrum.  It  would  seem,  therefore,  as  if  the  less  re- 
frangible rays  could  reverse  the  general  action  of  light  upon  iodide 
of  silver.  So  that,  while  every  ray  of  the  spectrum  is  capable  of  affect- 
ing this  substance,  the  more  refrangible  promote,  the  less  refrangible 
arrest,  this  general  action  of  light  upon  it. 

Bitumen  and  resins  also  receive  impressions  from  below  A  to  be- 
yond H,  every  ray  in  the  spectrum  acting.  In  the  bleaching  of 
flowers  by  light  "  the  rays  which  are  effective  in  the  destruction  of 
any  one  vegetable  color  are  precisely  those  which  by  their  union 
produce  a  tint  complementary  to  the  color  destroyed."  Chlorine 
and  hydrogen  unite  under  the  action  of  the  indigo  ray,  which  is  seven 
hundred  times  more  active  than  the  ultra-red.  Dr.  Draper  con- 
cludes, therefore,  "that  the  sensitiveness  of  any  given  preparation 
to  light  depends  on  its  chemical  nature  and  its  optical  qualities  con- 
jointly, and  that  it  is  possible  to  exalt  or  diminish  the  sensitiveness 
of  a  given  compound  by  changing  its  optical  relations." 

The  results  of  Dr.  Draper's  investigations  with  the  prismatic 
spectrum,  however,  were  not  altogether  satisfactory  to  him,  owing 
to  a  defect  which  originates  in  the  very  cause  which  gives  rise  to  the 
spectrum  itself — unequal  refrangibility.  If  we  compare  together 
two  sets  of  rays,  one  taken  in  the  red  and  the  other  in  the  violet 
region,  it  is  obvious  that,  in  the  same  spectrum,  from  the  very  cir- 
cumstance of  their  greater  refrangibility,  those  in  the  violet  will  be 
relatively  more  separated  from  each  other  than  those  in  the  red. 
The  result  of  this  increased  separation  in  the  more  refrangible 
regions  is  to  give  an  apparent  dilution  to  them,  while  the  less  re- 
frangible regions  are  concentrated. 

Accordingly,  in  May,  1843,  Dr.  Draper  succeeded  in  inducing 
Joseph  Saxton,  the  eminent  mechanician  of  the  United  States  mint 
at  Philadelphia,  to  rule  for  him  a  diffraction  grating.  With  this 
grating,  which  was  of  glass  and  five-eighths  of  an  inch  by  one-third 
of  an  inch  in  size,  the  diffraction  spectrum  was  produced  and  the 
above  difficulties  avoided.  Dr.  Draper  effected  a  great  improve- 
ment in  the  grating  by  silvering  its  ruled  surface  with  tin  amalgam, 
thus  producing  a  reflected  spectrum  which  was  far  more  brilliant 
than  the  transmitted  one,  though  he  suggested  that  perhaps  it  would 
be  better  to  rule  them  originally  on  steel  or  speculum  metal.  It 

3G7 


NATIONAL    ACADEMY    OF    SCIENCES. 

was  at  this  time,  too,  that  Dr.  Draper  suggested  that  the  different 
regions  of  the  spectrum  should  be  indicated  by  their  wave-lengths. 
"  Since  the  deviations  of  the  different  fixed  lines,  B,  C,  D,  in  the 
interference  spectrum,"  he  says,  "  are  proportional  to  the  lengths  of 
the  undulations  which  they  respectively  represent,  by  designating 
the  different  points  of  the  spectrum  by  their  wave-lengths,  the  sub- 
division may  be  carried  to  any  degree  of  minuteness  ;  the  measures 
of  one  author  will  compare  with  those  of  another  and  the  different 
phenomena  of  chemical  changes  occurring  through  the  agency  of 
light  become  allied  at  once  with  a  multitude  of  other  optical  re- 
sults." 

It  was  with  this  grating  that  the  diffraction  spectrum  was  for  the 
first  time  photographed.  A  daguerreotype  plate,  rendered  sensitive 
by  iodine  and  then  by  bromine,  and  exposed  for  half  an  hour,  gave 
a  maximum  sensitiveness  at  wave-length  0.00001538  Paris  inch. 
A  plate  prepared  by  iodine,  bromine,  and  chloride  of  iodine,  and  ex- 
posed for  an  hour,  gave  a  maximum  at  the  same  point,  the  decom- 
position extending  from  wave-length  0.00002007  in  the  green  to 
0.00001257  in  the  violet.  In  these  photographs  the  fixed  lines  were 
beautifully  distinct. 

Dr.  Draper,  too,  was  among  the  first  to  point  out  the  unsatisfac- 
tory character  of  the  measurements  which  have  been  made  with  the 
prismatic  spectrum  on  the  distribution  of  heat.  Since  the  less  re- 
frangible regions  are  much  compressed  and  the  more  refrangible 
much  dilated,  the  measures  obtained  by  means  of  a  uniform  move- 
ment through  the  spectrum  cannot  be  accepted  as  expressing  the 
true  distribution.  Hence,  in  1857,  he  attempted  to  determine  the 
curve  of  distribution  in  a  diffraction  spectrum ;  but  the  results,  though 
suggestive,  were  not  conclusive.  Subsequently,  in  1872,  he  devised 
a  simple  modification  of  the  prismatic  spectrum  method,  which  ac- 
complished practically  the  result  which  he  had  desired  to  obtain 
with  the  interference  spectrum.  Using  Angstrom's  values  expressed 
in  ten  millionths  of  a  millimeter,  the  wave  length  of  the  line  A  is 
7,604  and  that  of  H2  3,933,  these  lines  bounding  very  nearly  the 
visible  spectrum.  The  middle  point  is,  therefore,  at  5,768.  If, 
now,  the  heat  be  determined  first  in  the  region  from  7,604  to  5,768, 
and  then  from  5,768  to  3,933,  may  not  the  question  of  its  uniform 
distribution  be  thus  settled  ?  Upon  making  the  experiment  it  was 
found  that  the  two  halves  of  the  spectrum  gave  identically  the  same 
amount  of  heat,  and  this  whatever  be  the  material  of  the  prisms. 

368 


.JOHN    WILLIAM    DlIAl'KK. 

Hence  it  follows  that  any  two  series  of  undulations  in  the  spectrum 
will  have  the  same  heating  power,  no  matter  what  their  wave- 
lengths may  be. 

Continuing  his  spectrum  investigations,  Dr.  Draper  next  sought 
to  determine  the  law  of  the  distribution  of  light.  Mosotti,  in  Italy, 
had  already  studied  the  diffraction  spectrum,  and  had  shown  that 
the  maximum  of  illuminating  power  lay  in  the  yellow,  the  intensity 
declining  symmetrically  on  either  side.  The  photometric  method 
of  Bouguer  Dr.  Draper  had  used  in  1847,  with  good  results,  to 
measure  the  intensity  of  the  light  radiated  from  incandescing  plat- 
inum ;  and  he  now,  in  1879,  sought  to  construct  a  spectrometer  on 
the  same  principle  which  should  measure  light-intensity.  The  prin- 
ciple is  a  well-recognized  one  in  optics.  It  is  that  any  light  becomes 
invisible  in  presence  of  another  light  sixty-four  times  as  strong.  If, 
as  Mosotti  had  maintained,  the  yellow  be  the  brightest  of  the  spec- 
trum colors,  then  in  presence  of  an  extraneous  light  thrown  on 
the  spectrum  and  variable  at  will,  the  yellow  will  remain  after  the 
red  and  orange  on  the  one  side,  and  the  green,  blue,  and  violet  on 
the  other,  have  been  extinguished.  But  on  making  the  experiment, 
throwing  the  extinguishing  white  light  through  the  third  telescope 
of  an  ordinary  spectroscope,  so  as  to  reflect  it  to  the  eye  from  the 
face  of  the  prism,  Dr.  Draper  found  that  the  colors  of  a  gas-flame 
spectrum  disappeared  in  the  inverse  order  of  their  refrangibility, 
the  red  being  the  last  to  disappear.  Analogous  experiments  with 
the  spectrum  of  sunlight,  which  was  sometimes  thrown  on  a  screen 
and  sometimes  on  the  ground  glass  of  a  camera  and  extinguished 
by  daylight,  gave  precisely  similar  results.  On  gradually  opening 
the  shutter  admitting  the  daylight,  the  extreme  violet  disappeared 
first,  and  then  the  other  colors  in  the  inverse  order  of  refrangibility 
as  before.  On  closing  the  shutter  the  red  first  came  into  view,  and 
then  the  other  colors  successively.  Obviously,  if  this  result  is  due 
to  the  compression  at  the  red  end  of  the  prismatic  spectrum,  then  it 
should  not  be  found  in  that  produced  by  diffraction ;  and  on  mak- 
ing the  experiment  Dr.  Draper  saw,  not  without  pleasure,  that  as 
the  intensity  of  the  extinguishing  beam  increased  all  the  colored 
spaces  yielded  apparently  in  an  equal  manner  and  disappeared  at 
the  same  moment.  On  diminishing  the  intensity  of  the  extraneous 
light  he  observed  that  they  all  came  into  view  apparently  at  the 
same  time.  The  yellow,  as  before,  showed  no  superiority  over  the 
other  colors  in  resisting  extinction.  It  would  seem,  therefore,  that 

309 


NATIONAL    ACADEMY    OF    SCIENCES. 

the  apparent  brightness  of  the  yellow,  as  seen  by  the  eye,  is  a  purely 
physiological  phenomenon. 

Another  subject  to  which  Dr.  Draper  devoted  a  large  share  of 
attention  was  phosphorescence.  In  his  first  memoir  on  this  subject, 
published  in  1851,  he  discusses  the  general  character  of  the  phenom- 
enon, and  restricts  the  term  phosphorescent  to  those  bodies  which 
shine  in  the  dark  after  exposure  to  light  or  on  being  heated.  Fluor- 
spar, of  the  variety  known  as  chlorophane,  which  yields  a  superb 
emerald-green  light,  was  selected  for  experiment,  He  found  that 
when  made  to  phosphoresce  by  the  electric  spark  it  underwent  neither 
expansion  nor  contraction,  nor  any  other  molecular  change  detectable 
in  polarized  light.  He  did  observe  a  minute  evolution  of  heat,  but 
could  detect  no  electrical  change.  Nor  did  the  presence  of  a  pow- 
erful magnetic  field  appear  to  affect  the  result.  On  measuring  the 
amount  of  light  emitted  it  appeared  that  this  splendid  green  light 
was  photographically  twenty- four  times,  and  photometrically  three 
thousand  times,  less  intense  than  that  of  the  small  flame  of  an  oil 
lamp  taken  for  comparison.  But  he  noticed  that  the  quantity  of 
light  emitted  by  a  phosphorescent  body  was  proportional  to  the  in- 
tensity of  the  light  to  which  it  had  been  exposed.  In  1844  Dr. 
Draper  determined  that  the  special  phosphorogenic  rays  of  the 
spectrum  were  the  violet  rays.  In  this  research  he  used  a  quartz 
train  and  threw  the  spectrum  upon  a  screen  covered  with  calcium 
sulphide.  He  observed,  further,  that  for  the  transient  light  of  the 
spark  quartz  is  transparent  but  glass  is  opaque — that  is,  so  far  as  a 
surface  of  calcium  sulphide  is  concerned,  though  not  a  sensitive 
silver  surface.  Moreover,  while  glass  is  opaque  to  phosphorogenic 
rays  from  the  spark,  it  transmits  freely  those  from  incandescent  lime, 
so  that  the  calcium  light,  the  light  of  an  oil  lamp,  and  sunlight  can 
excite  phosphorescence  through  glass ;  that  of  the  electric  spark  or 
of  the  voltaic  discharge  in  mercury  cannot.  If,  however,  the  latter 
be  continuous  an  effect  is  produced  even  through  glass. 

In  his  last  scientific  memoir,  published  near  the  close  of  1880, 
Dr.  Draper  called  attention  to  the  striking  resemblance  existing 
between  a  photograph  of  the  solar  spectrum  taken  on  silver  iodide 
and  a  phosphorograph  taken  on  luminous  paint.  The  former,  when 
taken  in  presence  of  a  weak  extraneous  light,  shows  the  three 
regions  which  were  pointed  out  by  him  in  1842  :  (1 ),  a  middle  region, 
extending  from  the  boundary  of  the  green  and  blue  to  a  little  be- 
yond the  violet ;  here  the  silver  iodide  is  blackened  ;  (2),  below  this 

370 


JOHN    WILLIAM     DRAPER. 

and  extending  from  the  green  to  the  ultra-red  is  a  strongly-marked 
region  in  which  the  action  of  daylight  has  been  altogether  arrested 
or  removed,  the  daylight  and  the  sunlight  having  apparently  coun- 
terbalanced and  checked  one  another  ;  and  (3),  a  similarly  protected 
region,  much  shorter,  beyond  the  violet.  The  phosphorograph,  in 
the  absence  of  extraneous  light,  shows  a  shining  region  correspond- 
ing to  number  one  of  the  photograph.  But  if  foreign  light  inter- 
venes there  is  annexed  to  this  region  another,  including  the  less 
refrangible  spaces,  of  decided  blackness,  broken,  however,  at  a  short 
distance  below  the  red  by  a  luminous  rectangle  of  considerable 
width,  formed  by  the  coalescence  of  the  bands  «, /5,  Y-  There  is  also 
a  similar  but  smaller  region  in  the  violet.  In  this  memoir  Dr. 
Draper  notices  the  rapidity  with  which  the  red  spectrum  rays  ex- 
tinguish phosphorescence. 

The  electrical  investigations  which  were  undertaken  by  Professor 
Draper  were  much  fewer  in  number  than  those  on  light.  One  of 
the  most  important  of  these  was  a  paper  on  the  electromotive  power 
of  heat,  published  in  1840,  in  which  he  discusses  the  electromotive 
force  developed  in  pairs  of  different  metals  as  the  temperature  rises 
and  gives  values  for  wires  of  copper-iron,  silver-palladium,  iron- 
palladium,  platinum-copper,  iron-silver,  and  iron-platinum,  obtained 
with  one  junction  kept  at  32°  and  the  other  raised  either  to  212°  or 
to  6G2°F.  He  gives  curves  of  the  thermo-electric  action  of  these 
metals,  the  abscissas  being  temperatures  and  the  electromotive  forces 
ordinates,  constituting  a  thermo-electric  diagram.  In  this  diagram 
the  curves  of  iron-palladium  and  copper-silver  are  concave  toward 
the  axis  of  abscissas,  while  those  of  iron-platinum,  copper-platinum, 
and  silver-palladium  are  convex  toward  this  axis.  He  observed 
also  that  the  increase  of  electromotive  force  with  temperature  dif- 
fered for  the  different  pairs.  He  calls  attention  to  the  anomalous 
results  which  are  given  by  pairs  into  which  iron  enters,  and  gives 
the  diagram  of  a  copper-iron  couple,  the  maximum  ordiuate  of  which 
is  at  650°  and  the  neutral  point  at  a  temperature  at  which  an  alloy 
of  equal  parts  of  brass  and  silver  melts.  The  paper  concludes  with 
several  suggestions  in  regard  to  the  forms  which  it  is  desirable  to 
give  to  the  components  of  a  thermo-electric  couple. 

In  1834  he  studied  the  action  of  the  galvanic  battery  and  pub- 
lished an  account  of  some  improvements  in  its  construction  which 
his  experiments  had  suggested.  In  1835  he  repeated  the  experi- 
ments of  Morichini  and  Mrs.  Somerville  on  the  reputed  magnetiz- 

371 


NATIONAL    ACADEMY    OF    SCIENCES. 

ing  effect  of  violet  light,  and  came  to  the  conclusion  that  there  was 
no  evidence  whatever  to  sustain  the  opinions  of  these  experi- 
menters. In  1839  he  published  a  somewhat  extended  paper  on  the 
use  of  a  secondary  wire  as  a  measure  of  the  relative  tension  of  elec- 
tric currents,  describing  the  construction  and  use  of  a  torsion  gal- 
vanometer and  discussing  a  method  of  measuring  electro-motive 
force  by  the  fall  in  the  deflection  when  a  wire  of  high  resistance 
was  included  in  the  circuit.  He  also  considers  in  this  paper  the 
relations  of  electro-motive  force  and  of  resistance  to  the  current  pro- 
duced. In  1843  a  paper  on  the  law  of  the  conducting  power  of 
wires  gave  the  results  of  his  measurements  made  to  solve  the  prob- 
lem of  transmitting  electric  impulses  through  long  lengths  of  a 
conductor,  a  research  undertaken  to  aid  his  colleague,  Professor 
Morse,  in  perfecting  his  electro-magnetic  telegraph.  In  this  paper 
the  author  shows  that  the  diminution  of  the  strength  of  an  electric 
current  itself  diminishes  rapidly  with  increase  of  length  in  the  wire, 
and  that  generally  the  conducting  effect  of  wires  may  be  represented 
by  a  logarithmic  curve. 

The  purely  chemical  researches  published  by  Dr.  Draper  were 
also  few  in  number.  Among  these  may  be  mentioned  his  memoirs 
on  the  analysis  of  certain  ancient  coins  and  medals  (which  seemed 
to  him  to  prove  the  possibility  of  diffusion  in  solids)  on  micro-chem- 
istry, on  the  constitution  of  the  atmosphere,  on  respiration,  on  the 
allotropisrn  of  chlorine,  on  the  existence  and  effects  of  allotropism 
in  the  constituent  elements  of  living  beings,  on  a  singular  property 
of  gun-cotton  mixture,  and  on  a  new  method  for  the  determination 
of  urea. 

In  1844,  in  a  volume  on  the  forces  which  produce  the  organiza- 
tion of  plants,  Dr.  Draper  published,  as  an  appendix,  the  scientific 
memoirs  of  his  which  had  appeared  up  to  that  time  bearing  on  this 
question,  and  in  1873,  in  a  book  entitled  "  Scientific  Memoirs,"  he 
collected  together  the  papers  which  he  had  published  upon  Radiant 
Energy  and  closely  allied  subjects. 

During  the  later  years  of  his  life  Professor  Draper  devoted  his 
time  much  more  largely  to  literary  than  to  scientific  work.  Upon 
his  appointment  to  the  chair  of  physiology  in  1850  he  turned  his 
attention  once  more  to  physiological  subjects,  and  in  1856  he  collected 
together  the  matter  which  he  had  carefully  elaborated  in  his  class 
lectures  into  his  "  Human  Physiology,  Statical  and  Dynamical." 
This  book  marked  a  new  departure  in  the  science  of  physiology, 

372 


JOHN    WILLIAM    DRAPER. 

since  it  contained  not  only  the  results  of  his  valuable  original  in- 
vestigations on  various  important  subjects,  illustrated  by  his  own 
admirable  micro-photographs,  but  also  clear  and  forcible  discus- 
sions of  the  applications  of  strictly  scientific  theory  to  a  region 
heretofore  almost  entirely  given  over  to  a  hypothetical  vital  force. 
"Among  the  new  experiments  and  explorations  which  it  contained 
may  be  mentioned  the  condensing  action  of  membranes,  the  cause 
of  the  coagulation  of  the  blood,  the  theory  of  the  circulation  of  the 
blood,  the  explanation  of  the  flow  of  sap,  the  endosmotic  action  of 
thin  films,  the  measure  of  the  force  of  endosmose,  the  respiration  of 
fishes,  the  action  of  the  organic  muscle-fibers  of  the  lungs,  the  allot- 
ropisrn  of  living  systems,  the  action  of  the  skin,  the  functions  of  the 
nerve  vesicles  and  their  electrical  analogies,  the  functions  of  the 
sympathetic  nerve,  the  explanation  of  certain  parts  of  the  auditory 
apparatus,  particularly  of  the  cochlea  and  semicircular  canals,  the 
theory  of  vision,  and  the  theory  of  muscular  contraction."  This 
treatise  took  at  once  a  recognized  rank  as  a  text-book,  both  in  this 
and  other  countries,  and  was  translated  into  several  foreign  lan- 
guages, and  even  into  Russian. 

Perhaps  it  was  quite  natural  that  a  philosophic  mind  like  Draper's 
should  be  led  by  these  studies  to  formulate  a  sort  of  socialistic  physi- 
ology and  to  trace  in  the  working  of  communities  and  nations  the 
same  laws  which  control  the  evolution  of  the  individual.  But  how- 
ever this  may  be  the  "  Physiology  "  was  followed,  in  the  course  of 
a  few  years,  by  what  many  have  considered  his  most  brilliant  work, 
"A  History  of  the  Intellectual  Development  of  Europe,"  published 
in  1863.  "  The  object  of  this  work  was  mainly  to  point  out  that 
the  intellectual  progress  of  nations  proceeds  in  the  same  course  as 
the  intellectual  development  of  the  individual ;  that  the  movement 
of  both  is  not  fortuitous,  but  under  the  dominion  of  law ;  that  the 
stages  of  personal  development  are  paralleled  by  the  stages  of  social 
development,  and,  indeed,  as  paleontology  has  proved,  by  the  evolu- 
tion of  all  animated  nature,  and  that  there  is  an  ascent  of  man 
through  well-marked  epochs  from  the  most  barbarous  to  the  most 
highly  civilized  condition."  In  short  it  was  designed  to  be  an 
argument  in  favor  of  evolution  and  the  reign  of  law  in  the  historical 
development  of  the  world.  Few  philosophical  works  have  attained 
to  celebrity  so  quickly.  It  ran  rapidly  through  many  editions  in 
this  country  and  was  translated  into  nearly  every  European  lan- 
guage. The  Westminster  Review  said  of  it :  "  It  is  one  of  the  not 

373 


NATIONAL    ACADEMY    OF    SCIENCES. 

least  remarkable  achievements  in  the  progress  of  positive  philosophy 
that  has  yet  been  made  in  the  English  tongue — a  noble  and  even 
magnificent  attempt  to  frame  an  induction  of  all  the  recorded  phe- 
nomena of  European,  Asiatic,  and  North  African  history.  Unaccus- 
tomed though  a  reader  might  be  to  scientific  habits  of  thought  or 
uninterested  in  the  gradual  elaboration  of  eternal  rules  and  princi- 
ples, here  he  can  at  least  disport  himself  amid  noble  galleries  of 
historic  paintings  and  thrill  again  at  the  visions  of  the  touching 
epochs  that  go  to  fomi  the  drama  of  the  mighty  European  past. 
What  Comte  showed  might  and  ought  to  be  done  for  the  whole  world 
of  man;  what  Buckle  commenced  for  England,  Scotland,  France 
and  Spain,  Draper  has  effected  for  the  whole  of  Europe.  The 
gigantic  vastness  of  the  task  is  almost  paralyzing."  So  too  the 
Athenaeum :  "  It  is  no  light  commendation  to  say  that  its  execution 
is  not  altogether  unequal  to  its  magnitude.  If  it  were  equal  the 
world  would  place  Dr.  Draper  on  one  of  the  very  highest  pinnacles  of 
intellectual  achievements.  His  tenacity  and  completeness  of  grasp 
makes  itself  felt  for  the  most  part  on  every  page." 

In  1864  the  Historical  Society  of  New  York  invited  Dr.  Draper 
to  deliver  a  course  of  four  lectures  upon  some  subject  in  gen- 
eral political  economy.  These  lectures  were  afterward  expanded 
and  published  the  following  year  under  the  title,  "  Thoughts  on  the 
Future  Civil  Policy  of  America."  They  treated  :  (1)  on  the  influ- 
ence of  climate  upon  man ;  (2)  on  the  effects  of  emigration;  (3)  on 
the  political  force  of  ideas,  and  (4)  on  the  natural  course  of  national 
development.  These  lectures  "  contained  discussions  of  several 
interesting  points  which  since  that  time  have  largely  occupied  pub- 
lic attention,  such  as  the  internal  emigration  from  the  Atlantic 
States  to  the  West,  the  Asiatic  emigration  to  the  Pacific  States,  the 
political  effects  of  polygamy  in  Utah,  the  tendency  of  democratic 
institutions  to  centralization,  and  a  comparison  of  the  European 
with  the  American  method  of  government." 

The  line  of  investigation  thus  entered  upon  resulted  in  his  under- 
taking a  far  more  serious  labor,  the  preparation  of  a  "  History  of 
the  American  Civil  War,"  a  work  upon  which  he  was  almost  con- 
tinuously engaged  for  several  years  immediately  following  the  close 
of  this  war,  and  which  appeared  in  three  large  volumes  during  the 
years  between  1867  and  1870.  He  had  been  urged  to  enter  upon 
this  work  by  the  earnest  request  of  persons  who  had  been  chief 
actors  in  the  events  described  and  who  rendered  him  effective  aid. 

374 


JOHN    WILLIAM    DKAl'ER. 

Mr.  Stanton,  the  Secretary  of  War,  issued  orders  to  the  adjutant 
general  of  the  army  of  the  United  States  to  "  furnish  him  copies  of 
all  orders,  reports,  correspondence,  telegraphic  dispatches,  or  other 
documents  on  file  in  the  War  Department  as  he  might  request,  and 
to  permit  him  to  inspect  and  have  copies  of  any  maps,  plans,  and 
other  papers  necessary  for  the  preparation  of  his  work,  and  to  fur- 
nish him  with  statistical  information  respecting  the  armies  of  the 
United  States,  their  organization  and  operations."  This  order  in- 
cluded also  all  the  Confederate  archives  in  possession  of  the  War 
Department.  Nor  was  the  interest  of  the  Secretary  of  War  limited 
to  this.  He  supplied  a  large  amount  of  personal  information  of  the 
utmost  value.  Access  was  not  unfrequently  given  the  author  to 
documents  and  correspondence  of  the  most  confidential  kind,  with 
a  view  of  guiding  him  to  correct  conclusions  ;  and  many  of  the  most 
decisive  military  operations  are  detailed  from  private  memoranda 
furnished  by  the  commanding  officers  themselves. 

The  last  literary  work  on  which  Dr.  Draper  was  engaged  was  the 
"  History  of  the  Conflict  between  Religion  and  Science,"  issued  in 
1874  as  one  of  the  volumes  of  the  International  Scientific  series. 
Much  of  the  material  utilized  in  this  volume  is  said  to  have  been 
matter  originally  intended  for  the  "  Intellectual  Development  of 
Europe."  The  book  attempted  to  trace  the  development  of  the  an- 
tagonism which  has  ever  been  present  between  the  conservative  and  * 
the  scientific  elements  of  thought,  between  the  ecclesiastical  and  old 
on  the  one  side  and  the  radical  and  new  on  the  other.  The  former, 
always  opposed  to  the  progress  of  the  latter,  has  sought  in  all  times 
to  hinder  this  progress  by  every  means  it  could  devise  lest  forsooth 
some  of  its  antiquated  tenets  should  require  modification.  The  title 
of  the  book  has  sometimes  been  criticised  on  the  ground  that  relig- 
ion is  a  personal  element  entirely,  and  with  this,  of  course,  science 
can  never  be  in  antagonism.  But  using  the  word  in  the  broader 
sense,  in  which  Dr.  Draper  used  it — as  synonymous  with  ecclesiasti- 
cism  and  theology — there  always  has  been  a  conflict  between  them 
and  there  always  will  be  so  long  as  they  both  shall  exist.  The 
favor  with  which  this  book  was  received  was  something  surprising. 
In  the  first  ten  years  of  its  existence  it  passed  through  more  than 
twenty  editions  in  the  English  language  and  was  translated  into 
French,  Spanish,  German,  Dutch,  Russian,  Italian,  Portuguese, 
Polish,  and  Servian.  It  has  even  been  placed  on  the  Index  Ex- 
purgatorius  of  the  Romish  church,  an  honor  which  its  author  has 

375 


NATIONAL   ACADEMY    OF    SCIENCES. 

shared  with  Galileo,  with  Copernicus,  with  Kepler,  with  Locke,  and 
with  Mill. 

In  all  his  literary  work  Dr.  Draper's  methods  were  always  of  the 
same  high  character  as  those  which  distinguished  his  scientific  in- 
vestigations. He  showed  alike  in  both  the  same  close  and  impartial 
scrutiny  of  the  facts,  the  same  careful  and  minute  examination  of 
all  the  conditions  which  they  involved,  the  same  conscientious  and 
exact  record  of  the  results  obtained.  After  passing  the  ordeal  of 
his  severe  criticism  his  work  had  little  to  fear  from  outside  attack. 
All  that  he  did  was  pervaded  by  the  high  moral  tone  which  char- 
acterized the  man.  If  he  was  scrupulously  accurate  in  observing 
and  testing  his  facts  and  in  drawing  inferences  from  them,  if  he 
was  ingenious  in  devising  and  skillful  in  applying  crucial  tests  to 
detect  error  or  misconception,  he  was  equally  honest  in  placing  his 
observations  and  conclusions  on  record  and  in  according  to  his  con- 
temporaries and  co-workers  the  full  share  of  praise  to  which  they 
were  entitled. 

It  is  not  easy  to  estimate  the  value  of  Dr.  Draper's  services  as  a 
teacher.  From  the  time  of  his  appointment  to  the  professorship  in 
Hampden  Sidney  College  in  1836  until  the  year  before  his  death— 
a  period  of  forty-five  years — he  was  constantly  occupied  in  the 
work  of  instruction.  Of  the  facilities  at  his  disposal  when  he  first 
went  to  New  York  he  thus  speaks  :  "  Our  laboratory  was  then  in  a 
little  dark  back  room  without  ventilation.  The  morning  sun  strug- 
gled almost  in  vain  to  see  what  we  were  doing,  for  the  window- 
panes  were  covered  with  an  incongruous  arrangement  of  Venetian 
blinds  and  Gothic  mullions.  A  hole  in  the  ceiling  led  up  to  the 
chapel  above,  to  the  pulpit  of  which  the  material  for  the  daily 
lecture  was  carried  in  a  tea-tray.  I  called  it  a  pulpit,  because  they 
used  to  preach  out  of  it.  A  clergyman,  who  also  statedly  occupied 
it,  regarded  it  as  a  pneumatic  trough,  because  I  experimented  in  it. 
And  this,  I  think,  it  really  was,  for,  recalling  the  Greek  etymology 
of  that  epithet,  it  plainly  indicates  the  double  function,  spiritual 
as  well  as  chemical.  Our  laboratory  work  commenced  at  seven  in 
the  morning  and  continued  uninterruptedly  till  after  midnight,  and, 
as  might  have  been  leadily  foreseen,  what,  with  the  impure  air  and 
mental  application,  the  individual  chiefly  engaged  twice  contracted 
a  fever  and  narrowly  escaped  with  his  life."  Dnring  the  ten  years 
from  1840  to  1850  he  gave  a  series  of  introductory  lectures  to  the 
medical  classes  in  the  university,  which  are  among  the  best  popular 

376 


JOHN    WILLIAM    DRAPER. 

expositions  of  the  applications  of  science  to  medicine  to  be  found 
in  the  language.  These,  as  well  as  his  valedictory  lectures,  were 
generally  printed  by  the  classes  to  which  they  were  severally  ad- 
dressed. According  to  competent  authority  they  were  "  clear  in 
statement,  fresh  and  striking  in  their  views,  and  lively,  poetic,  and 
witty,  as  well  as  instructive,  well  fitted  to  awaken  the  students'  en- 
thusiasm." Those  on  the  relations  of  chemistry  to  medicine,  on  the 
history  of  chemistry,  on  atmospheric  air,  on  water,  on  oxygen,  and 
on  phosphorus  are  spoken  of  as  having  been  exceptionally  sugges- 
tive and  brilliant. 

Dr.  Draper  appeared  but  rarely  upon  the  platform  of  the  public 
lecturer.  In  1853  he  made  an  address  before  the  Alumni  Associa- 
tion upon  "The  Indebtedness  of  the  City  of  New  York  to  its  Uni- 
versity," which  was  a  strong  plea  for  science  in  education.  In  1863 
he  gave  the  anniversary  discourse  before  the  New  York  Academy 
of  Medicine,  the  subject  of  which  was  "  The  Historical  Influence  of 
the  Medical  Profession."  His  lectures  before  the  Historical  Society 
in  1864  have  already  been  mentioned.  As  president  he  addressed 
the  American  Union  Academy  at  its  first  annual  meeting  in  1870. 
His  felicitous  address  at  the  farewell  dinner  to  Professor  Tyndall, 
given  in  New  York  in  February,  1873,  and  his  inaugural  address 
as  president  of  the  American  Chemical  Society  on  "Science  in 
America,"  delivered  in  1876,  are  among  his  happiest  efforts.  One 
of  the  most  noteworthy  of  his  public  addresses  was  that  upon  Evo- 
lution, delivered  before  the  Unitarian  Institute,  in  Springfield,  in 
October,  1877. 

Besides  the  work  which  Dr.  Draper  did  in  pure  science  he  was 
closely  connected  with  the  development  of  two  of  the  most  impor- 
tant inventions  ever  made.  One  of  these  was  the  electro-magnetic 
telegraph  of  Morse,  the  other  was  the  art  of  photography.  In  one 
of  his  addresses  to  the  alumni  (1853)  he  gives  the  following  account  of 
the  evolution  of  the  telegraph:  "Fourteen  years  ago  there  stood 
upon  the  floor  of  the  chemical  laboratory  of  our  University  a  pair  of 
old-fashioned  galvanic  batteries.  Like  the  cradle  of  a  baby,  they 
worked  upon  rockers,  that  so  the  acid  might  be  turned  on  or  off. 
A  gray-haired  gentleman  had  been  using  them  for  many  years  to 
see  whether  he  could  produce  enough  magnetism  in  a  piece  of  iron 
at  a  distance,  to  move  a  pencil  and  make  marks  upon  paper.  He 
had  contrived  a  brass  instrument  that  had  keys  something  like  a 
piano  in  miniature,  only  there  was  engraven  on  each  a  letter  of  the 

377 


NATIONAL   ACADEMY    OF   SCIENCES. 

alphabet.  When  these  were  touched  the  influence  of  the  batteries 
was  sent  through  a  copper  wire  and  a  mark  answering  to  a  letter 
was  made  a  long  way  off.  *  *  *  But  long  after  the  telegraphic 
instruments  were  perfected  it  was  doubtful  whether  intelligence 
could  be  sent  to  any  considerable  distance.  It  is  one  thing  to  send 
an  electric  current  a  few  yards  and  a  totally  different  affair  to  send 
it  a  thousand  miles.  Experiments  which  had  been  made  under  the 
auspices  of  the  Russian  government  by  Professor  Jacobi,  of  the 
University  of  Dorpat,  had  led  to  the  inference  that  the  law  of  the 
conducting  power  of  wires,  originally  discovered  in  Germany,  was 
correct ;  and,  in  addition,  a  corroborative  memoir  had  been  read  by 
Lenz  before  the  Imperial  Academy  of  Sciences  at  St.  Petersburg. 
At  this  time  so  little  was  known  in  England  as  regards  this  impor- 
tant point,  that  some  of  the  most  eminent  natural  philosophers  con- 
nected with  universities  there  embraced  the  opposite  view.  I  may 
not  be  able  to  make  the  precise  point  in  dispute  clear;  it  was  this : 
A  current  passing  through  a  certain  length  of  wire  suffers  a  certain 
amount  of  loss.  If  it  should  go  through  a  wire  a  thousand  times 
as  long  will  the  loss  be  a  thousand  times  as  great  ?  The  Russians 
said  yes  ;  the  English  said  no.  If  the  former  was  the  case  it  was 
universally  concluded  that  the  electric  telegraph  would  not  be  prac- 
ticable for  any  considerable  distance.  A  series  of  experiments  was 
made  in  the  University  of  New  York  which  established  beyond  all 
question  the  truth  of  the  Russian  view.  But  at  that  time  the  higher 
mathematics  were  cultivated  in  our  laboratory,  as  well  as  mere  ex- 
perimenting ;  and  on  submitting  the  results  to  such  a  mathematical 
discussion  the  paradoxical  conclusion  was  brought  out  that  it  is  a 
necessary  consequence  of  that  law  that  after  a  certain  length  of 
wire  has  been  used  the  losses  become  imperceptible.  Encouraged 
by  this,  a  party  of  gentlemen  went  with  the  inventor  of  the  telegraph 
to  a  rope-walk  near  Bloomingdale,  one  summer  morning,  and  there 
tested  the  truth  of  these  conclusions  on  lengths  of  wire  varying  from 
one  to  some  hundreds  of  miles.  The  losses  of  the  currents  were 
measured  by  the  quantity  of  gas  set  free  in  the  decomposition  of 
water.  The  result  was  completely  successful,  and  telegraphing  for 
any  distance  became  an  established  certainty." 

The  part  which  he  took  in  the  evolution  of  photography  he  thus 
describes :  **  When  the  French  government,  in  1839,  purchased  of 
Daguerre  his  invention  of  photogenic  drawing,  its  applications  were 
very  limited.  The  process  was  adapted  to  interiors,  statuary,  and 

378 


JOHN    WILLIAM    DRAPER. 

architectural  subjects,  but  wholly  unsuited  to  landscape  scenery  or 
to  portraits.  The  inventor  himself  had  made  attempts  at  applying 
it  to  the  taking  of  likenesses,  but  had  given  it  up  in  despair.  Soon 
after  the  publication  of  Daguerre's  invention  in  America  a  series 
of  experiments  was  conducted  in  our  laboratory  with  a  view  of  de- 
termining whether  the  difficulties  could  be  removed."  The  results 
were  successful,  and  the  taking  of  portraits  from  life  by  daguerreo- 
type became  before  long  an  everyday  operation. 

The  great  value  of  Dr.  Draper's  contributions  to  science  has  been 
cordially  recognized  by  the  highest  authorities.  Melloni,  the  creator, 
as  it  were,  of  the  science  of  radiant  heat,  warmly  congratulated  him 
on  his  memoir  on  this  subject,  presented  an  abstract  of  it  to  the 
Royal  Academy  of  Sciences  at  Naples,  and  in  his  own  subsequent 
memoir  warmly  commends  the  ingenuity  and  ability  of  the  Amer- 
ican scientist.  Herschel  was  equally  cordial  in  praise  of  his  photo- 
chemical researches.  Berzelius,  a  few  days  before  his  death,  sent 
to  Dr.  Draper  his  portrait  with  a  kind  message  conveying  his  ap- 
preciation of  what  he  had  done  for  science.  Kirchhoff,  in  1862, 
thus  speaks  of  his  heat  experiments :  "  Draper  has  derived  from  ex- 
periment the  conclusion  that  all  solid  bodies  begin  to  glow  at  the 
same  temperature,  but  he  has  observed  in  his  experiments  that  cer- 
tain bodies,  as  chalk,  marble,  and  fluor-spar,  shine  at  a  lower  tem- 
perature than  they  should  according  to  this  law;  he  calls  this  light 
phosphorescent  and  observes  that  it  is  distinguished  from  the  glow 
by  its  color.  But  whatever  name  may  be  given  to  the  light  it  con- 
tradicts the  law,  and  a  body  which  shows  it  cannot  satisfy  the  as- 
sumption which  is  made  in  proving  the  law ;  it  cannot  remain  un- 
changed, the  temperature  remaining  the  same  ;  the  phosphoresence 
is  not  the  simple  influence  of  heat,  it  is  not  exclusively  conditioned 
on  temperature,  but  it  is  caused  by  changes  in  the  body  ;  if  these 
changes,  be  they  chemical  or  of  any  other  kind,  cease,  then  the 
phosphoresence  must  also  vanish."  Bunsen  and  Roscoe  have  recog- 
nized Dr.  Draper  most  fully  as  the  pioneer  in  the  investigation  of 
the  action  of  light  upon  chlorine,  a  subject  worked  out  successfully 
by  them. 

Dr.  Draper  was  elected  a  member  of  many  of  the  learned  societies 
of  Europe,  among  them  the  Accademia  dei  Lincei,  at  Rome,  and 
the  Physical  Society  of  London.  In  1843  he  was  elected  a  member 
of  the  American  Philosophical  Society  at  Philadelphia,  and  in 
1860  he  received  the  degree  of  LL.  D.  from  the  college  of  New 

379 


NATIONAL   ACADEMY   OF   SCIENCES. 

Jersey  at  PrincetoD.  In  1875  the  American  Academy  of  Arts 
and  Sciences  at  Boston  awarded  to  him  the  Rumford  medals  for 
his  reseaches  on  Radiant  Energy.  In  his  speech  of  presentation 
the  Hon.  Charles  Francis  Adams,  then  president  of  the  Academy, 
after  recapitulating  the  reasons  given  by  the  committee  for  recom- 
mending this  award,  said  to  Mr.  Quincy,  who  was  deputed  in  Dr. 
Draper's  absence  to  receive  the  medals :  "  I  pray  you,  in  receiving 
these  two  medals  on  his  behalf,  in  accordance  with  the  terms  of  the 
original  trust,  to  assure  him  on  the  part  of  the  Academy  of  the  high 
satisfaction  taken  by  all  its  Fellows  in  doing  honor  to  those  who, 
like  him,  take  a  prominent  rank  in  the  advance  of  science  through- 
out the  world."  In  his  letter  of  reply  Dr.  Draper  says  :  "  Your 
favorable  appreciation  of  my  researches  on  radiation,  expressed  to- 
day by  the  award  of  the  Rumford  medals — the  highest  testimonial 
of  approbation  that  American  science  has  to  bestow  on  those  who 
have  devoted  themselves  to  the  enlargement  of  knowledge — is  to 
me  a  most  acceptable  return  for  the  attention  I  have  given  to  that 
subject  through  a  period  of  more  than  forty  years.  *  *  *  It 
adds  impressively  to  the  honor  you  have  this  day  day  conferred  on 
me  that  your  action  is  the  deliberate  determination  of  competent, 
severe,  impartial  judges.  I  cannot  adequately  express  my  feelings 
of  gratitude  in  such  a  presence,  publicly  pronouncing  its  approval 
of  what  I  have  done." 

Professor  Draper  was  not  elected  a  member  of  the  National 
Academy  of  Sciences  until  1877.  It  is  not  easy  to  understand  at 
this  late  day  why  a  man  so  eminent  in  science  was  not  included 
among  the  original  incorporators  of  the  Academy.  An  attempt,  it 
is  believed,  was  made  to  remedy  this  apparent  oversight  during  the 
meeting  which  was  held  in  New  York  in  1863  for  organization,  but 
for  some  unexplained  reason  the  effort  failed.  So  uncalled  for  an 
action  on  the  part  of  the  Academy  rendered  it  for  some  time  doubt- 
ful whether  he  would  accept  the  membership  when  it  was  subse- 
quently tendered. 

Dr.  Draper  was  married  at  quite  an  early  age.  While  a  student 
at  the  University  of  London  in  the  year  1830,  then  nineteen  years 
old,  he  boarded  with  a  friend  of  his  father's,  Mrs.  Barker  by  name, 
where  he  met  her  niece,  Miss  Antonia  Gardner,  who  was  then 
residing  with  her  and  attending  a  young  ladies'  school  in  the 
neighborhood.  This  young  lady  was  the  daughter  of  Dr.  Gardner, 
of  Rio  Janeiro,  the  attending  physician  of  the  Emperor  of  Brazil, 


JOHN    WILLIAM    DRAPER. 

Dom  Pedro  I.  Though  himself  an  Englishman  Dr  Gardner 
had  married  into  the  celebrated  de  Piva-Pereira  family  of  Portu- 
gal, and  this,  their  only  daughter,  had  been  brought  to  London 
to  complete  her  education.  Within  a  few  months  they  became 
engaged,  and  in  1831,  not  long  after  the  death  of  her  father,  in 
Brazil,  they  were  married.  In  1832  Dr.  Draper's  father  also  died, 
and  his  mother  accompanied  the  newly-married  couple  across 
the  ocean  to  settle  among  the  little  Wesleyan  colony  in  Vir- 
ginia, where  she  died  in  the  following  year.  It  was  to  his  ac- 
complished wife  that  Dr.  Draper  owed  much  of  the  happiness 
which  characterized  his  married  life.  Six  children  were  born  to 
them,  one  of  whom  died  in  infancy.  The  eldest  son,  John  Chris- 
topher Draper,  was  born  in  Virginia  in  1835  and  became  his 
father's  successor  as  professor  of  chemistry  in  the  medical  de- 
partment of  the  University  of  New  York.  He  died  on  the  20th  of 
December,  1885.  The  second  son,  Henry  Draper,  was  born  in  1837 
also  in  Virginia.  He  became  professor  of  physiology  in  the  univer- 
sity and  subsequently  professor  of  analytical  chemistry.  He  early 
turned  his  attention  in  the  direction  of  physical  research,  especially 
in  its  application  to  astronomy,  and  was  elected  a  member  of 
the  National  Academy  in  1877.  His  early  death  in  1882  alone 
prevented  his  rising  to  an  equal  eminence  as  an  investigator 
with  that  attained  by  his  distinguished  father.  The  third  son, 
Daniel  Draper,  is  at  present  the  director  of  the  Meteorological  Ob- 
servatory in  Central  Park,  New  York.  Dr.  Draper's  daughters 
were  Virginia,  afterward  Mrs.  Maury,  named  for  the  State  in  which 
she  was  born,  who  died  in  October,  1885,  leaving  three  children  ; 
and  Antonia,  who  is  at  present  Mrs.  Edward  H.  Dixon. 

Any  record  of  the  Draper  family,  however,  which  did  not  men- 
tion Dr.  Draper's  elder  sister  Catherine  would  be  quite  incomplete. 
As  already  mentioned,  she  accompanied  the  newly-married  couple 
across  the  ocean  when  they  removed  to  America.  Having  shared 
her  brother's  tastes  for  scientific  studies,  she  became  his  assistant  in 
research  and  rendered  him  most  valuable  aid.  Her  portrait  was 
the  first  ever  taken  from  the  life  by  the  daguerreotype  process,  and 
the  colored  plates  which  illustrate  his  memoirs  were  the  work  of 
her  pencil.  She  was  a  constant  inmate  in  his  family,  and  during 
the  many  years  of  Mrs.  Draper's  ill  health  she  was  as  a  mother  to 
the  children.  She  has  outlived  her  brother,  and  resides  still  at  the 
family  mansion  in  Hastings. 

(3)  381 


NATIONAL    ACADEMY    OF    SCIENCES. 

On  coming  to  New  York  Dr.  Draper  occupied  at  first  a  house 
in  Charles  street,  subsequently  removing  to  the  corner  of  Broad- 
way and  Amity  street.  But  in  1848  he  purchased  a  delightfully 
located  piece  of  property  at  Hastings  upon  the  Hudson,  where  he 
lived  until  his  death.  It  was  here  that  Henry  Draper  built  his 
observatory ;  and  in  this  building  the  father  and  son  spent  many  a 
pleasant  hour  together  engaged  in  that  most  delightful  of  occupa- 
tions, the  pursuit  of  scientific  knowledge. 

Dr.  Draper,  though  somewhat  below  the  average  stature,  was  a 
man  of  fine  personal  presence.  He  was  mild  in  manner  and  quiet 
in  demeanor,  having  very  little  of  self-assertion.  The  excellence  of 
his  disposition  and  the  charm  of  his  personal  intercourse  drew  to 
him  warm  and  disinterested  friends  on  every  hand.  He  was  an 
extensive  reader  and  his  conversational  powers  were  remarkably 
developed,  so  that  he  always  had  attentive  listeners,  whether  the 
subject  of  his  discourse  was  literary  or  scientific.  But  it  was  when 
he  opened  his  rich  storehouse  of  personal  reminiscence  that  his 
auditor  was  most  charmed  and  delighted.  His  health,  which  through 
life  had  been  generally  good,  was  disturbed  during  his  later  years  by 
severe  attacks  of  gravel,  which  incapacitated  him  for  journeying. 
These  attacks  wore  upon  him  and  finally  ended  his  life.  He  died 
at  Hastings,  on  the  4th  of  January,  1882,  and  was  buried  at  Green- 
wood. 

In  the  eloquent  words  of  Professor  Lovering,  "  Dr.  Draper's  mind 
was  too  large  to  be  shut  up  within  the  walls  of  his  laboratory.  To 
him  the  minutest  facts  were  of  value,  but  only  as  they  furnished  the 
key  for  interpreting  the  Universal  Cosmos  of  nature  and  humanity. 
In  clear  and  graceful  language  the  best  that  was  in  his  thoughts 
was  shared  by  the  world.  There  was  a  continuity  in  his  life-work, 
plain  to  himself,  if  not  obvious  to  the  superficial  observer.  He  says  : 
'  When  I  thus  look  back  on  the  subjects  that  have  occupied  my 
attention  I  recognize  how  they  have  been  interconnected,  each  pre- 
paring the  way  for  its  successor.  Is  it  not  true  that  for  every  person 
the  course  of  life  is  along  the  line  of  least  resistance,  and  that  in 
this  the  movement  of  humanity  is  like  the  movement  of  material 
bodies?'" 


382 


PUBLICATIONS  OF  JOHN  WILLIAM  DRAPER. 

I.— SCIENTIFIC  MEMOIRS. 

1832. 

On  volcanoes.  By  W.  M.  Higgins  and  J.  W.  Draper.  Mai/.  X«f.  Hist., 
v,  104-174,  2(52-272,  6:J2-OJ}7 ;  vi,  344-350,  1832. 

Remarks  on  the  formation  of  the  Dead  Sea  and  the  surrounding  district. 
I5y  W.  M.  Higgins  and  J.  W.  Draper.  May.  Mif.  ///'.s^.,  v,  532-534,  1832. 

1833. 

Remarks  on  electrical  decompositions.  By  William  M.  Higgins,  F.  G.  S., 
and  ,}.  W.  Draper  (dated  110  Chancery  Lane,  August,  1832).  Edinb.  New 
Phil.  Juurn.,  xiv,  314-317,  April,  1833. 

1834. 

Influence  of  electricity  on  capillary  attraction.  (Extract  of  a  letter  from 
Jno.  W.  Draper  to  the  editor,  dated  Christiansville,  Mecklenburg,  Va.,  May 
31st,  1832*.)  Am.  J.  Sci.,  I,  xxvi,  399,  July,  1834. 

Some  experimental  researches  to  determine  the  nature  of  capillary  attrac- 
tion. J.  Fr.  Inst,  xiv,  147-105,  September,  1834. 

An  account  of  some  experiments  made  to  determine  the  best  construction 
of  galvanic  batteries  of  four  elements.  J.  Fr.  Inst.,  xiv,  289-295,  Novem- 
ber^ 1834. 

Chemical  analysis  of  native  chloride  of  carbon.  J.  Fr.  Inst.,  xiv,  295-298, 
November,  1834. 

1835. 

Experiments  to  determine  whether  light  exerts  magnetic  action.  J.  Fr. 
Inst.,  xv,  79-85,  155-158,  February.  March,  1835. 

Idolatry  and  philosophy  of  the  Zabians.  Am.  J.  Sci.,  I,  xxviii,  201,  July, 
1835. 

On  the  chemical  analysis  of  coins  and  medals.  Am.  J.  Sci.,  xxix,  157-160, 
October,  1835.  (Bibliotheyue  Universelle  1835,  370-374.  Froriep  Notl- 
zen,  xlix,  7-9.) 

1836. 

On  the  tidal  motions  of  conductors  free  to  move.  J.  Fr.  Inst.,  xvii,  27-33, 
January,  1830. 

Experiments  on  absorption.     Am.  J.  Med.  Sci.,  xviii,   13-32,  May,  1836. 

Experiments  on  endosmosis.  ,/.  Fr.  Inst.,  xvii,  177-182;  xviii,  27-31, 
March,  July,  1830.  (Phil.  Mag.,  Ill,  xi,  559,  December,  1837.) 

Observations  on  microscopic  chemistry.  J.  Fr  Inst.,  xviii,  378,  Decem- 
ber, 1836. 

*  This  must  be  a  misprint  for  ls:H,  since  at  this  date,  in  1832,  Draper  had  not  yet  left 
England. 

383 


NATIONAL    ACADEMY    OF    SCIENCES. 

1837. 

Experiments  on  solar  light.  Am.  J  Mcd.  Sei.,  xx,  208,  May,  1837;  J. 
Fr.  Inst.,  xix,  409-479,  June  ;  xx,  38-46,  July  ;  114-121,  August :  250-255, 
October,  1837.  (Sturgeon'1  s  Ann.  Elcc.,  ii,  397-399,  1838.) 

liemurks  on  the  action  of  presence.  Am.  ,/.  Mnl.  ,SV/.,  xxi,  123-130,  No- 
vember, 1837.  (Froriep  Nottzen,  II,  v,  257-250,  1839.) 

1838. 

Simultaneous  meteorological  observations.  J.  Fr.  Inst.,  xxi,  39,  Janu- 
ary, 1838. 

On  the  physical  action  of  capillary  systems.  Identification  of  the  force 
producing  motion  with  the  chemical  force  (dated  November  20,  1837).  Am. 
J.  Mf.d.  Set.,  xxi,  289-302,  February,  1838. 

On  some  mechanical  functions  of  areolar  tissues.  Containing  the  co-ordi- 
nation of  the  diffusion  laws  of  Professor  Graham  and  the  experiments  of 
Dr.  J.  K.  Mitchell  and  the  general  laws  of  equilibrium.  Am.  J.  Med.  Set., 
xxii,  23-44,  May;  302-323,  August,  1838. 

Remarks  on  the  constitution  of  the  atmosphere.  Phil.  Mat/.,  Ill,  xxii, 
241-252,  October,  1838. 

1839. 

Further  remarks  on  the  action  of  presence.  Am.  J.  Med.  Sei.,  xxiii, 
08-81,  September,  1839. 

On  the  use  of  a  secondary  wire  as  a  measure  of  the  relative  tension  of 
electric  currents.  Phil.  Mag.,  Ill,  xv,  200-279,  October;  339-349,  Novem- 
ber, 1839.  (Bibliotheque  Universelle,  xxiv,  170-179,  1840.) 

1840. 

An  account  of  some  experiments  made  in  the  south  of  Virginia  on  the 
light  of  the  sun.  Phil.  Mag.,  Ill,  xvi,  81-84,  February,  1840.  (Froriep 
Notizen,  II,  xili,  337-341.) 

On  the  electromotive  power  of  heat.  Pldl.  Mag.,  Ill,  xvi,  451-401, 
June,  1840. 

On  the  process  of  daguerreotype  and  its  application  to  taking  portraits 
from  the  life.  Pldl.  Mag  ,  III,  xvi*  535,  June;  xvii,  217,  September,  1840. 
(Sturgeon's  Ann.  Elec.,  vi,  503-504.) 

1841. 

On  some  analogies  between  the  phenomena  of  the  chemical  rays  and  those 
of  radiant  heat.  Pldl.  Mag.,  III.,  xix,  195-210,  September,  1841. 

1842. 

On  certain  spectral  appearances  and  on  the  discovery  of  latent  light. 
Phil,  Mag.,  Ill,  xxi,  348-350,  November,  1842.  Am.  J.  Sci.,  I,  xliv,  202, 
October- December,  1842. 

On  a  new  imponderable  substance  and  on  a  class  of  chemical  rays  anal- 
ogous to  the  rays  of  dark  heat.  Phil.  Mag.,  Ill,  xxi,  453-461,  December, 
1S42.  (Froriep  Notizen,  II,  xxv,  1-8,  17-23,  1843.) 

384 


JOHN    WILLIAM    DKAPEK. 

1843. 

On  the  rapid  detithoni/ing  ])owor  of  certain  gases  and  vapors,  and  on  an 
instantaneous  means  of  producing  spectral  appearances.  Phil.  Mm/.,  Ill, 
xxii,  101-105,  March,  1K43.  (Sturyeon'x  Ann.  Elcc.,  x,  402-4(55.  Frorirp 
ATo/;-r/,,  II,  xxv,  :J40-:J43,  1843.) 

On  a  new  system  of  inactive  tithonographic  spaces  in  the  solar  spectrum 
analogous  to  the  fixed  lines  of  Fraunhofer.  Phil.  May.,  III,  xxii,  300-364, 
May,  1843. 

On  the  tithonotype,  or  art  of  multiplying  daguerreotypes.  Phil.  May., 
Ill,  xxii,  305,  May,  1843. 

On  the  decomposition  of  carbonic-acid  gas  and  the  alkaline  carbonates  by 
the  light  of  the  sun,  and  on  the  tithonotype.  Proc.  An/.  Phil.  Soc.,  iii,  111- 
114,  May,  1843.  Phil.  Mat/.,  Ill,  xxiii,  161-170,  September,  1843.  (Rep. 
Jirif.  Axxoc.,  1843,  Pt.  2,  33-34;  Chemist,  1843,  iv,  444-445  ;  Am.  J.  Sri., 
I,  xlvi,  :5!)8,  1844;  Ann.  <1hu»,  /%*.,  xi,  214-228,  1844;  J.  Pr.  Ckem.,  xxxi, 
21-30,  1844;  Napoli  Rendi  Conto,  iii,  297-300,  1844.) 

On  the  law  of  the  conducting  power  of  wires.  Am.  J.  Sci.,  I,  xlv,  392, 
.July-September,  1843  (Arc/do,  de  I'Elec.,  vi,  329-330,  1844). 

On  a  change  produced  by  exposure  to  the  beams  of  the  sun  in  the  proper- 
ties-of  an  elementary  substance.  Rep.  Brit.  Assoc.,  1843,  Pt.  2,  9.  Phil. 
Ma;/.,  Ill,  xxiii,  388,  November,  1843.  (Chemist,  iv,  442-443,  1843;  Am. 
J.  ,SW,,  I,  xlvi,  390,  January-March,  1844.) 

Description  of  the  tithonometer  [chlorhydrogen  photometer]  ;  an  instru- 
ment for  measuring  the  chemical  force  of  the  indigo-tithonic  rays.  Phil. 
May.,  Ill,  xxiii,  401-405,  December,  1843;  Am.  J.  Sci.,  I.  xlvi,  217-232, 
January-March,  1844. 

1844. 

On  Mr.  Hunt's  book  entitled  "Researches  on  Light."  Phil.  May.,  Ill, 
xxv,  49,  July,  1844. 

On  tithonizcd  chlorine.  (Read  at  the  meeting  of  the  British  Association 
in  Cork  in  1843.)  Phil.  May.,  Ill,  xxv,  1-10,  July,  1844. 

Further  considerations  on  the  existence  of  a  fourth  imponderable.  Phil. 
Ma,/.,  Ill,  xxv,  103-110,  August,  1844. 

Note  on  the  decomposition  of  carbonic  acid  by  the  leaves  of  plants  under 
the  influence  of  yellow  light.  Phil.  May.,  Ill,  xxv,  169-173,  September, 
1844. 

1845. 

Is  capillary  action  an  electrical  phenomenon?  Phil.  May.,  Ill,  xxvi, 
185-189,  March,  1845. 

On  the  interference  spectrum  and  the  absorption  of  the  tithonic  rays. 
Phil.  Mm/.,  Ill,  xxvi,  405-478,  June,  1845. 

On  the  allotropism  of  chlorine  as  connected  with  the  theory  of  substitu- 
tions. Am.  J.  Sci..,  I,  xlix,  340-308,  July-September,  1845.  Phil.  Ma,,., 
Ill,  xxvii,  327-340,  November,  1845.  (Kibl.  Universelle,  Ix,  305-379,  1845; 
J.  Pr.  Chem.,  xxxvii,  103-109,  1840;  J.  Pharm.,  ix,  398-399,  1840.) 

385 


NATIONAL    ACADEMY    OF    SCIENCES. 

Account  of  a  remarkable  difference  between  the  rays  of  incandescent  lime 
and  those  emitted  by  an  electric  spark.  Phil.  Mag.,  Ill,  xxvii,  435-437, 
December,  1845. 

1846. 

On  the  cause  of  the  circulation  of  the  blood.  Phil.  May.,  Ill,  xxviii, 
178-189,  March,  1840  ;  Am.  J.  ScL,  II,  ii,  276-279,  September,  1846.  (Fro- 
riep  Notizen,  II,  xxxvii,  289-296,  305-311.) 

1847. 

Kemarks  on  the  existerce  and  mechanism  of  the  protecting  or  negative 
rays  of  the  sun.  Phil.  Mag.,  Ill,  xxx,  87-93,  February,  1847.  (Biblio- 
theque  Universelle.  v,  5-14,  1847;  J.  de  Pharm.,  xii,  152-154,  1847.) 

Singular  property  of  gun-cotton  mixture.  Phil.  Mag.,  Ill,  xxx,  299, 
April,  1847. 

On  the  production  of  light  by  heat.  Phil.  Mag.,  Ill,  xxx,  345-360,  May, 
1847  ;  Am.  J.  ScL,  II,  iv,  388-402,  November,  1847.  (Froriep  Notizen,  III, 
iv,  97-102,  113-119,  1847.) 

1848. 

On  the  production  of  light  by  chemical  action.  Phil.  Mag.,  Ill,  xxxii, 
100-114,  February,  1848;  Am.  J.  ScL,  II,  v,  159-172,  March,  1848.  (Fro- 
riep  Notizen,  III,  vii,  17-24,  33-37,  1848.) 

1849. 

On  the  existence  and  effects  of  allotropism  in  the  constituent  elements  of 
living  beings.  Phil.  Mag.,  Ill,  xxxiv,  241-246,  April,  1849. 

1851. 

On  the  phosphorescence  of  bodies.  Phil.  Mag.,  IV,  i,  81-100,  February, 
1851. 

On  the  chemical  action  of  light.  Phil.  Mag.,  IV,  i,  368-393,  May,  1851. 
(J.  de  Pharm.,  xx,  253-258,  1851.) 

1852. 
On  respiration.     Am.  J.  Med.  ScL,  II,  xxiii,  314-320,  January,  1852. 

1853. 

On  a  new  method  for  the  determination  of  urea.  Phil.  Mag.,  IV,  vi,  290- 
292,  October,  1853. 

1857. 

On  the  diffraction  spectrum.     Phil.  Mag.,  IV,  xiii,  153-156,  March,  1857. 

On  the  measurement  of  the  chemical  action  of  light.  Phil.  Mag.,  IV, 
xiv,  161-164,  September,  1857.  (J.  Phot.  Soc.,  iv,  34-36,  1858.) 

On  the  influence  of  light  upon  chlorine  and  some  remarks  on  alchemy. 
Phil.  Mag.,  IV,  xiv,  321,  November,  1857. 

1858. 

On  the  nature  of  flame  and  on  the  condition  of  the  sun's  surface.  Phil. 
M<KJ.,  IV,  xv,  90-93,  February,  1858;  Am.  J.  ScL,  II,  xxvi,  268-271,  Sep- 
tember, 1858. 

386 


JOHN    WILLIAM    DRAPER. 

1863. 

On  the  motions  of  camphor  toward  the  light.  Phil.  Mag.,  IV,  xxv,  38, 
January,  18G3. 

On  the  motions  of  camphor  toward  the  light  and  on  variations  in  the  fixed 
lines  of  the  solar  spectrum.  Phil.  Mag.,  IV,  xxv,  342-344,  May,  1803. 

1872. 

Researches  in  actino-chemistry.  Memoir  first.  On  the  distribution  of  lieat 
in  the  spectrum.  Phil.  Mag.,  IV,  xliv,  104-117,  August,  1872  ;  Am.  J.  Sc.i., 
Ill,  iv,  101-175,  September,  1872. 

Researches  in  actino-chemistry.  Memoir  second.  On  the  distribution  of 
chemical  force  in  the  spectrum.  Phil.  Mag.,  IV,  xliv,  422-443,  December, 
1872;  Am.  J.  Sci.,  Ill,  v,  25-38,  January,  91-98,  February,  1873. 

1877. 

On  the  fixed  lines  in  the  ultra-red  invisible  region  of  the  spectrum.  Phil. 
M<I<I.,  V,  iii,  8G-88,  February,  1877. 

1879. 

Political  effect  of  the  decline  of  faith  in  Continental  Europe.  Princeton 
Review,  January,  1879. 

On  a  new  form  of  spectrometer  and  on  the  distribution  of  the  intensity  of 
light  in  the  spectrum.  Am.  J.  Sci.,  Ill,  xviii,  30-35,  July,  1879  ;  Phil.  Mag. , 
V,  viii,  75-81,  July,  1879. 

1880. 

On  a  new  standard  of  light.     Phil.  Mag.,  V,  ix,  76,  January,  1880. 

On  the  phosphorograph  of  a  solar  spectrum  and  on  the  lines  in  its  infra- 
red region.  Proc.  Am.  Ac.ad.,  xvi,  223,  December,  1880;  Am.  J.  Sci,  III, 
xxi,  171-183,  March,  1881  ;  Phil.  Mag.,  V,  xi,  157-109,  March,  1881. 

II.— BOOKS. 

Elements  of  chemistry.  By  Robert  Kane.  American  edition  edited  by 
John  William  Draper.  One  volume,  8vo.,  pp.  704,  New  York,  1842. 

A  treatise  on  the  forces  which  produce  the  organization  of  plants,  with  an 
appendix.  One  volume,  4to.,  pp.  108,  216,  New  York,  1844. 

Text-book  on  chemistry.     One  volume,  12mo.,  pp.  412,  New  York,  1840. 

Text-book  on  natural  philosophy.  One  volume,  12mo.,  pp.  381,  New 
York,  1847. 

Human  physiology — statical  and  dynamical.  One  volume,  8vo.,  pp.  649, 
New  York,  1856. 

History  of  the  intellectual  development  of  Europe.  One  volume,  8vo., 
pp.  631,  New  York,  1862. 

Thoughts  on  the  future  civil  policy  of  America.  One  volume,  8vo.,  pp. 
325,  New  York,  1865. 

A  text-book  on  physiology.  One  volume,  12  mo.,  pp.  376,  New  York,  1800. 

History  of  the  American  civil  war.  Three  volumes,  8vo.,  pp.  567,  014, 
701,  New  York,  1867-1870. 

387 


NATIONAL    ACADEMY    OF    SCIENCES. 

History  of  the  conflict  between  religion  and  science.  One  volume,  12mo., 
pp.  373,  New  York,  1874. 

Scientific  memoirs ;  being  experimental  contributions  to  a  knowledge  of 
radiant  energy.  One  volume,  8vo.,  pp.  473,  New  York,  1878. 

III.- LECTURES  AND  ADDRESSES. 

On  the  relations  of  chemistry  to  medicine.  A  lecture  introductory  to  the 
course  in  chemistry,  University  of  New  York,  medical  department.  De- 
livered November  1,  1841.  35  pages. 

On  the  theory  and  phenomena  of  heat.  The  concluding  lecture  of  that 
part  of  the  chemical  course  in  the  medical  department  of  the  University  of 
New  York.  Delivered  by  Professor  J.  W.  Draper,  November  22d,  1841. 
10  pages. 

A  valedictory  lecture.     Delivered  in  March,  1842.     14  pages. 

On  the  relations  of  atmospheric  air  to  animals  and  plants.  A  lecture  in- 
troductory to  the  course  on  chemistry,  medical  department,  University  of 
New  York.  Delivered  October,  1844.  10  pages. 

On  the  relations  and  nature  of  water.  Introductor}^  lecture  to  the  course 
on  chemistry,  medical  department.  Delivered  November  1, 1845.  15  pages. 

On  the  history  of  chemistry.  An  introductory  lecture  to  the  chemical 
course,  medical  department.  Delivered  October  30,  1840.  15  pages. 

On  phosphorus.  An  introductory  lecture  to  the  chemical  course,  medi- 
cal department.  Delivered  October  30,  1847.  14  pages. 

On  oxygen  gas.  An  introductory  lecture  to  the  course  in  chemistry, 
medical  department.  Delivered  October,  1848.  15  pages. 

The  influence  of  physical  agents  on  life.  An  introductory  lecture  to  the 
course  on  chemistry  and  physiology,  medical  department.  Delivered  Octo- 
tober,  1850.  14  pages. 

The  indebtedness  of  the  city  of  New  York  to  its  university.  An  address 
to  the  alumni  at  their  twenty-first  anniversary,  held  on  the  28th  of  June, 
1853.  30  pages. 

The  historical  influence  of  the  medical  profession.  An  anniversary  dis- 
course. Delivered  before  the  New  York  Academy  of  Medicine,  December 
10,  1803.  32  pages. 

Professional  education.  A  lecture  introductory  to  the  course  of  1809- '70 
in  the  medical  department.  Delivered  October  18,  1809.  10  pages. 

Address  delivered  to  the  American  Union  Academy  of  Literature,  Science, 
and  Art  at  its  first  annual  meeting,  January  31,  1870.  By  J.  W.  Draper, 
president.  24  pages. 

Science  in  America.  An  inaugural  address  before  the  American  Chemi- 
cal Society.  By  Dr.  John  W.  Draper,  president.  Delivered  November  10, 
1876.  (American  Chcndxt,  December,  1876;  Am.  J.  Sci.,  Ill,  xiii,  01-07, 
January,  1877.) 

Evolution — its  origin,  progress,  and  consequences.  An  address  to  the 
Unitarian  Institute  at  Springfield,  Mass.,  October  11, 1877.  Popular  Science 
Monthly,  December,  1877. 


THE  UNIVERSITY  LIBRARY 

UNIVERSITY  OF  CALIFORNIA,  SANTA  CRUZ 

SCIENCE  LIBRARY 

This  book  is  due  on  the  last  DATE  stamped  below. 


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